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How to Prevent Frozen Pipes in Winter: Move Water Lines Indoors

Updated on June 15, 2017

For many years, I lived in a little hamlet which I will call Plumbing Hell—mainly because there was no city water. In remote rural areas where people rely on a cistern, a pump, and a water-hauler, the home water supply is often precarious.

Winter meant a continuous struggle with frozen lines. This was mainly because no one felt comfortable about leaving their water running in very cold weather. Why? Because you could run your cistern dry—run out of water—which would burn up your $500 pump. Plus, if the roads were bad, your water-hauler might be unable to bring you more.

In such remote rural areas, plumbing is a survival skill, and literally everyone I knew there (except for newcomers) was an expert plumber. As you can probably guess, since I lived to tell about it, I too became an expert plumber—mainly under the tutelage of my neighbor, who was a plumber’s daughter.

Old-timers in the town of Plumbing Hell learned to solve the problem of frozen water lines, once and for all: They moved their plumbing lines indoors.

It took several years for me to move my own plumbing indoors—or even to realize I should. Country people don’t like to tell other people what to do, possibly going on the assumption that you either don’t know how or can't afford to, or that you might try to get them to do it for you. Being as I was (in my case, a woman), I imagine the assumption was that I wouldn’t know how and would probably be very resistant to finding out—or possibly that I would try to get some guy to do it for me. The ladies are sometimes accused of this kind of thing. The fact that most people hate to do plumbing and often refuse to learn this rather simple skill is a very good reason to be a plumber. If I were a young person today, that is the trade I would go into.

Most normal people hate to do plumbing, but while there are admittedly some downsides, plumbing—especially with CPVC—is easy to both understand and do.

To move your water lines indoors, you will need to know a few plumbing basics. Here are the plumbing basics, and directions for moving your water lines indoors.

Why Are Your Pipes Freezing?

The answer to this question is pretty obvious: Some or all of your water lines are too exposed.

If your existing water lines are located in an uninsulated or poorly insulated crawl space, they get cold enough to freeze in winter. Mobile homes are particularly prone to frozen pipes, since the pipes usually run under the trailer. Trailers usually have no foundation, but instead have uninsulated vinyl skirting between the floor level and the ground. Vinyl skirting offers your water lines some protection, but not much. And in very cold weather, even a good foundation will not keep a crawl space warm enough to prevent pipes from freezing.

There are several ways to solve this problem:

  1. Insulate your foundation.
  2. Wrap all water lines that are exposed to cold with heat tape and insulation.
  3. Move your water lines inside.

Each of these options is described in full below.

Insulating Your Foundation—Pros and Cons

The first approach would be to insulate your foundation. As you know, if you only have crawl space, this could be a difficult and unpleasant job.

Crawl spaces usually have little headroom and are often obstacle courses. There is almost no telling what you might encounter in the crawl space of an older home. Heating ducts may further reduce headspace in some areas—possibly in the exact spot where you must also crawl over a septic line or drain line. Also, especially in an older house, crawl spaces are often full of dirt, debris, and spider webs. But at least there are probably no dangerous animals under there.

If you decide to insulate your foundation, I think the best (and easiest) approach would be to use rigid styrofoam insulation and apply it to the inside of the foundation with an adhesive. Cracks and gaps could be filled in with spray-foam insulation.

What If I Live in a Mobile Home?

  1. About the only way to insulate the non-existent foundation in a mobile home is to replace your skirting with plywood and insulate its inside surface with rigid styrofoam insulation. The kind that is three inches thick would be best.
  2. This approach basically involves building a stud wall from the ground (or, hopefully, the slab) to the underside of the trailer. It is obviously best if the bottom of this stud wall can rest on a slab, concrete block foundation, or concrete form, since it will rot if it must rest on the ground.
  3. Nail 3/4" plywood to the exterior of this low stud wall and attach rigid styrofoam insulation to the inside.
  4. The exterior plywood will of course need a protective finish of some kind, such as exterior paint.
  5. Also, be sure there is at least one (preferably two) openings in this structure to allow you to access the crawl space. These openings can be a simple as an easily removable panel.

This approach of building a low exterior wall to enclose your crawl space works really well if it's good and tight. It can actually keep a crawl space warmer than a more traditional foundation with chinks and cracks.

Wrapping Water Lines Under the House With Heat Tape and Insulation—Pros and Cons

Another solution is to crawl under the house and wrap all the pipes in heat tape and insulation.

Water pipes are normally insulated with long lengths of foam pipe insulation. These are slit down their entire length so that you can slip them over the pipes. (Tape them in place with duct tape.) This material is known in the construction trade as “donkey dick,” for obvious reasons. Should you ask for it by name? Maybe it would be best to ask for “pipe insulation,” but either term will be familiar to the guys in the plumbing aisle.

When insulating water pipes, it is best to wrap the hot and cold water lines together, if possible. CPVC hot and cold water lines are often run closely parallel to each other—even almost touching. It is done this way to make it possible to insulate them wrapped together—and also to avoid cutting two holes in the floor (one for each line). It’s easier to run both lines through a single hole in the floor. Plus, water lines are normally run using the most direct route possible, to conserve materials. This route is mostly the same for both lines.

For places where you are wrapping two water lines together, you’ll need to buy foam pipe insulation that is large enough in diameter to go around both lines.

Sometimes hot and cold water lines do not run close together and parallel to each other. This may be the work of former owners. Sometimes pipes must be heat-taped and insulated separately. Also, the cold-water line will branch off by itself to supply the toilet. This is because the hot water line does not run to the toilet. It is only supplied by cold water.

This method can work quite well, especially if your foundation is also in good shape and you keep those heat tapes plugged in. Heat tape for a house of any size may be an expense—plus you will probably need to drill a hole in the floor near an outlet, so that the heat tape can pass through the floor and be plugged in. You will want to think about where you are going to plug in the heat tape—the nearness of the outlet to the water lines under the floor, and the chances that the hole in the floor can be camouflaged. You could set a bookcase in front of it, for example.

This is another somewhat unpleasant job, because you have to crawl around under the house to do it. Another caveat about using this method: If one of your water lines leaks or breaks, it can be difficult to locate the problem. The pipes are all wrapped up. You will probably have to unwrap a lot of water pipe before you locate the leak or break. It will also be difficult to make a repair on a line that is wrapped in heat tape. You may have to take the heat tape off, as well. The end result is that you will have quite a lot of heat-taping and pipe-insulating to do over, after you make a repair.

Moving Your Water Lines Inside the House—the Ultimate Fix

This is the ultimate solution to the problem of frozen water lines. This is the way it is done by savvy do-it-yourselfer types.

The cause of frozen pipes is pretty obvious: Your water lines are in a cold location. Ergo, the answer is to move them to a warm location—indoors. I suffered through several years of frozen pipes, and several years of crawling under the house in winter to fix broken lines. Remember, I lived in Plumbing Hell. Once, while I was fighting these regular battles with the frozen pipes, a neighbor woman mentioned that many people move their plumbing indoors to keep the lines from freezing.

I thought this was just crazy talk.

One day my old buddy Mike, an elderly construction worker, was showing me his new pump, and remarked, “I ran all my lines indoors years ago.”

Now I knew it wasn’t just crazy talk. If Mike said it was okay, it was okay. Mike was, in most ways, quite sane—plus he knew more about construction work than anyone I’d ever met.

Later, when I mentioned moving my lines indoors, almost everyone I talked to said the same thing: “I ran all my lines indoors years ago.”

This kind of thing is very commonly done.

By the time I learned that this was a good idea, I had quite a few years of plumbing experience under my belt. I had dragged electrical cords for drop lights and saws through puddles of water in cramped, dark, and dirty conditions. I had dragged myself through puddles of water in freezing weather.

I was beginning to get annoyed. But, despite all those years of doing plumbing, moving the lines indoors seemed like a daunting project.

But it was also at this point in time that I had an epiphany. I realized that I had come to understand plumbing lines pretty well.

I looked at diagrams of house plumbing online and in my copy of Black and Decker’s The Complete Guide to Home Plumbing, and had another epiphany: It’s easy to understand this! I could easily just cut out the lines running under the house and replace them with new indoor lines running above the floor, instead of under it!

Since my house was plumbed throughout with CPVC, the job would be easy.

Why Use CPVC?

Some people feel that plumbing just isn’t real plumbing if it doesn’t involve flux and a heat torch—but plumbing with CPVC will not result in the revocation of your man card.

CPVC is real plumbing. In former times, the mantra of many plumbing companies was, “Everything’s going to CPVC.”

Nowadays, plumbers and plumbing supply stores often take a jaundiced view of CPVC. Why? I think, along with many others, that professional plumbers know that plumbing with CPVC is so simple that it is basically a ladies’ craft project—or like putting together Tinker Toys.

What Is CPVC?

CPVC (chlorinated polyvinyl chloride) is plastic pipe, intended for both hot and cold water lines. Many authorities, including Zenith Plastic's website, consider CPVC to be superior to metal pipes: “Life expectancy of plastic pipe systems far exceeds that of metal systems and requires simpler and less costly maintenance…. Materials are generally lower cost, light weight and easier to handle. Joining is accomplished through solvent cementing, threading, flanging or victaulic.”

In other words, CPVC plumbing is great in every way. There simply isn’t a downside.

CPVC pipes and fittings are attached together with CPVC glue (usually called “cement”)—after first applying CPVC primer/cleaner, just to make sure the glue adheres really well.

Yes, you heard me right. CPVC plumbing is glued together.

Hence, if you feel that you can manage to work with Tinker Toys and glue, you should be able to do all your home plumbing if you are using CPVC.

All you have to do is glue together a bunch of plastic pieces. Not much can go wrong.

  • CPVC is easy to cut to any length. I usually use a miter saw to cut it, but you can use a circular saw, or even a jigsaw, for tight places.
  • You can purchase every conceivable kind of CPVC fitting to make every conceivable kind of turn or connection.
  • Basic plumbing fittings are used to attach lengths of pipe together. Plumbing fittings come in Ts, elbows (or 90s), and straight couplings. If your water line needs to make a turn, you stick two lengths of pipe together with an elbow, or L-shaped coupling. If you need a line to branch off, you use a T-shaped coupling. To add length to a pipe, you use a straight coupling.
  • CPVC pipe is sold in various lengths, but 8-foot lengths are usually the most convenient. Pieces of CPVC pipe are called “sticks.”

If you are unfamiliar with plumbing, visit the plumbing aisle at your favorite hardware store, where you can familiarize yourself with these materials and chat with the guy in the plumbing aisle.

What's the Difference Between PVC and CPVC?

Home plumbing lines are normally made with half-inch CPVC, but you will notice that home improvement centers and hardware stores often sell both PVC and CPVC. What’s the difference, and which should you use?

  • The only real difference between PVC and CPVC is that CPVC will withstand higher temperatures. The maximum service temperature of PVC is 140°, whereas the maximum service temperature of CPVC is 210°. Other than that there is no difference.
  • It is sometimes recommended that you use PVC for cold-water lines and CPVC for hot-water lines.
  • My suggestion would be to use it for both hot and cold water lines. The difference in price is insignificant, and running all your lines using all the same material will save you a lot of aggravation—mostly from mistakenly buying the wrong fittings.

Laying Out the Plumbing Lines

Here are a couple of drawings that show the basic layout of plumbing lines. Notice that the main water line that comes from the curb may enter the house at either the hot-water heater or at the other end of the line—for example, at the kitchen sink.

When you look at these two diagrams, it will be clear that, in your house, most of these water lines are not where you can see them. They are mostly running under the floor, where it can get mighty cold. They do not need to be under the floor. They might just as well run above the floor, where it's warm. And, as an added bonus, you don't have to crawl under the house to repair them.

Figure 1
Figure 1

In Figure 1, the main water line from the curb (the heavy blue curved line at the bottom left) enters the house next to the hot-water heater. This is the normal arrangement—and in fact this is the way it is supposed to be done—so in all probability, your water line from the curb/meter comes into the house next to the hot-water heater.

Notice that the house’s (BLUE) cold water line runs the length of the house, branching, first, to supply the hot water heater and then branching to supply each plumbing fixture.

The (RED) hot-water line coming out of the top of the hot-water heater likewise runs the length of the house, branching to supply hot water to each plumbing fixture.

In Figure 1, both the hot and cold water lines end under the kitchen sink.

Even though this is the normal arrangement, it does not have to be done this way.


Figure 2
Figure 2

Figure 2 illustrates the “not normal” place for your main water line (the heavy blue line in the lower right-hand corner) to enter the house.

Notice that, in Figure 2, the (BLUE) water line from the curb/meter enters the house under the kitchen sink.

I include this drawing to alert you to the possibility that your home plumbing was not done in the normal way, and also to point out that these slightly “not normal” plumbing designs are actually perfectly okay.

The main water line form the curb/meter normally comes into the house at the water heater. But if you find that your water line from the curb/meter comes into the house under the kitchen sink, there was probably a very good reason for this. Most likely the reason is that the hot-water heater is way at the back of the house, and running the main water line to it would have entailed an extra 20-30 feet of line—and an extra 20-30 feet of trenching. Bringing the line in under the kitchen sink is a perfectly workable option, so why not?

Notice, in Figure 2, that as the cold-water line runs the length of the house, it branches off to supply cold water to each plumbing fixture and, finally, to supply the hot-water heater.

Simple, right?

Now notice the (RED) hot-water line. The hot-water line comes from the hot-water heater (duh) and runs the length of the house in the opposite direction, branching off to supply hot water to each plumbing fixture. The hot–water line ends at the kitchen sink.

If you look at these diagrams, you will see that the basic arrangement of home plumbing lines is simple.

It may occur to you that there are way more plumbing fixtures in your house than I have shown in these drawings. Where is the half bath? Where is the washing machine? Where is the dishwasher? Innumerable other items can be added to this diagram. Just draw in the washing machine and draw red and blue lines to it, branching off just as the others do.

Well—except for the dishwasher. The water line to the dishwasher is spliced into the hot-water line in the kitchen by a supply line, in the same way the hot-water faucet is, and could really be thought of as a kind of third faucet on the kitchen sink. It does not need its own branch from the main hot-water line.

Your plumbing lines will probably not be identical to either of these diagrams, but the principle will be the same. Could the hot-water heater be in the middle, instead of one end? Sure.

Does the water line from the curb enter your house at the water heater, or elsewhere? You will have to look.

Usually, the main water line will enter your house at the front, because the front of the house is nearest the city water main (or your meter) at the curb. When water lines are installed from the curb to the house, most builders would prefer not to make this line any longer than necessary, because it is costly in materials—but mainly time and labor—to lay this line. The water pipe itself costs money by the foot, and the line must be laid in a deep trench (four feet deep in my area of the country). Builders will prefer to keep this line as short as possible.

It would be unusual to find your water line from the curb entering the back of your house. To run this line all the way to the back of the house would involve digging a deep trench an additional 30 feet or more, plus laying an additional 30 feet or more of water line. It is usually not done that way.

On the other hand, it is not impossible. When my neighbor hooked up to city water, he wanted the line to come in at his hot-water heater, which was located near the back of his house. He had the trench dug and the line laid for the additional distance.

In rural areas, and especially where an owner has built a house and arranged for a city or county water hook-up, things are often done differently than they would be done by a suburban real-estate developer (who will have an eye to keeping costs to a minimum). A private individual might have his own ideas and preferences, and be willing to pay for them.

In general, it shouldn’t be hard to figure out how the pipes are running in your house. Have a look at the pipes in the crawl space, if you are in doubt. In a small home or mobile home, especially, it may be possible to easily surmise the layout of the pipes.

How Your Plumbing Lines Are Laid Out

So…you can see from these diagrams that water enters your house through an underground line that starts at the water main and runs into your house in the basement or crawl space. A trench was dug from the water main that runs along the street, to the house. Your main water line to the house was laid in this trench. This trench is supposed to be below the frost line, so that the underground line would never freeze in winter.

One end of this main water line is attached to the street water main—or to a meter at the curb. The other end runs up under your house and is attached to the beginning of your home’s cold-water line.

The water line that runs into your house form the curb is attached to the beginning of your home’s cold-water line. These two lines of differing materials are hooked together with a plumbing fitting intended for the two specific materials.

Since we are talking about CPVC plumbing, we will assume that your main water line to the house connects to a CPVC line.

This CPVC cold-water line should have a shut-off valve right where it begins, since this is where you shut off water to the whole house—in case a line breaks or you need to work on the plumbing.

This shut-off valve should be inside the house above floor-level, and not in the crawl space. Clearly, it should be where you can find and access it easily. Sometimes it needs to be where you can find it fast.

It is good to know where it is. In houses with basements, the main shut-off valve is probably in the basement. If your home has a crawl space and no basement, it should be located where the beginning of the cold-water line first enters the house—most likely at the hot-water heater.

Your Home Has Lots of Other Shut-Off Valves

Besides the main shut-off valve that turns off water to the whole house, each of your plumbing fixtures (including the hot-water heater) should be equipped with shut-off valves for both the hot and the cold water lines. Why? Because if you need to replace kitchen or bathroom faucets or replace the innards of your toilet tank, you need not turn off the water to the whole house to do so. You can just turn off water to the fixture you are working on—provided you are working only on parts that the shut-off valves shut off, of course.

When doing plumbing work of any kind, it may be most convenient to simply turn off water to the whole house, using the main shut-off valve. This is especially true if your home’s plumbing doesn’t have shut-off valves for each and every plumbing fixture.

Each and every plumbing fixture in your home should have shut-off valves, by the way. But sometimes a former owner may have installed a new sink or shower, and didn’t bother with shut-off valves. As a result of this lack of shut-off valves, plumbing work may require shutting off the water to the whole house.

People like me who are nervous and high-strung sometimes like to turn off water to the whole house when working on just about anything, even if it does have shut-offs. And if you are cutting water lines for any reason, you will want to shut off water to the whole house, and then run water from faucets to drain the lines as much as possible, before cutting into them. Otherwise, you (and your power tools) could get wet—perhaps very wet.

Figure 3
Figure 3

Now That You Know How Simple Plumbing Really Is, You Are Ready to Move Your Water Lines into the House?

Before going ahead with moving your water lines indoors, it is best to realize that this could take some time. The water to the house will be shut off completely while you are doing the work. Stock your house with ample bottled water. You may want to set aside a few buckets of water for flushing the toilet, as well, or fill your bathtub with water for flushing.

Your drain lines are unaffected by this work. You can still flush the toilet and pour water down the drains.

This is also a good time to purchase some paper plates and plastic silverware, unless you plan to eat out the whole time your water is shut off. This could be for a couple of days.

Figure 3 shows how the water lines run under the floor.

Notice that there is a hole in the floor everywhere a plumbing line comes up above the floor to supply a plumbing fixture. This is pretty silly in itself.

If you have another look at this diagram, you can see that if the darned lines that run under the house were moved just a few inches higher, they would be inside the house, where they wouldn’t freeze.

You may even wonder why the heck any sane person would locate plumbing lines in a cold crawl space to begin with.

As with many other things that are done kind of stupidly, the reason is cost.

Plumbing lines above floor level cannot run in a straight line from one end of the house to the other. Well, of course, they could. They could even be covered up in some way. But there would still be an unpleasing bump in the floor or under the carpet.

Generally, when running plumbing lines above the floor, you will want to put them around the perimeters of rooms. That way no one will trip over them. Once they have been cleverly covered up, no one will even know they are there.

In the process of planning just exactly where your plumbing lines will need to run, you will likely realize that they must pass through walls in some places. So you will have to drill some holes large enough for the water lines to pass through in some interior walls.

After you have thought this over, it will be easy to see why the builders didn’t do it this way to begin with. It will take quite a lot more feet of CPVC to run lines along the perimeters of rooms than it takes to run two straight lines the length of the house under the floor.

CPVC is inexpensive, but main additional cost of laying lines indoors is the additional labor. And of course additional materials would be required to cover up and hide water lines at the perimeter of rooms.

If you move all your water lines indoors yourself, the cost of materials will not be that great. But to you as a homeowner, the time savings are likely to be great. Moving water lines indoors will save you many hours of time spent crawling around under the house making repairs to lines that have frozen and broken. Plus you and your family will be assured of the convenience of running water, even in the coldest of winter weather.

How to Move the Pipes Above the Floor

There are several steps. This seems like a lot of steps, but several of them are a bit obvious. I have listed them mainly to clarify how to organize the job.

  1. Draw a diagram of where pipes will run inside the house.
  2. Decide how you will cover up pipes.
  3. Drill holes in interior walls as needed and shown in your diagram.
  4. Calculate the materials you will need to lay water pipes above the floor. Buy the necessary materials.
  5. Find all the places where the hot and cold water lines come up through the floor. You are going to cut them—all but one, that is—but not yet.
  6. Turn off water to the whole house at the main shut-off valve.
  7. Run water from house faucets until they stop running and the lines are dry.
  8. You have already located the main shut-off valve. DO NOT CUT BELOW IT!
  9. Next, you are going to cut all the other lines passing through the floor.
  10. Run new plumbing lines above the floor.
  11. Wait for CPVC glue to dry.
  12. Turn the water back on and check for leaks. Repair any leaks and wait for glue to dry again.
  13. Wrap the water line that is still under the house in heat tape and pipe insulation.
  14. Cover all exposed indoor plumbing lines so that they look nice.

Each of these steps is described in detail below.

1. Draw a diagram of where pipes will run inside the house.

The first step is to decide where you are going to lay the lines above floor level. It would be good to draw a diagram showing how you will route the plumbing lines through the house and where lines need to pass through interior walls.

Notice that the hot and cold water lines in the diagram (and probably under your house) run in a straight line.

They don’t have to run in a straight line when placed inside the house. They will have to turn a lot of corners to be run around the perimeter of rooms.

This is perfectly fine. Water will flow around an amazing number of corners with ease.

2. Decide how you will cover up pipes.

Before you begin laying the water lines indoors, you will probably want to consider how you will cover them up. They would be unsightly if left exposed.

You could plan on boxing them in with one-by lumber. That is, you could build a U-shaped box to lay over them.

The pipes could also be covered with corner guards, which are available in sizes up to three inches to a side, and they come in wood, vinyl, rubber, and metal.

Hollow moldings, intended to cover electrical cables and other home electric cords, are also available. Cable covers—also intended to hide indoor electrical cables and cords at the base of walls—could also be used.

It is essential to use some form of covering that is easily opened or removed. Plumbing lines should always be at least reasonably accessible.

Suppose you have examined your home’s floor plan and you have realized that there is no darned way that the water lines from the hot-water heater can be run to the kitchen or bathroom, or both, by running them around the perimeter of a room or rooms.

This “moving the water lines indoors” business works really well with single-wide trailers and other small homes. Usually these are designed so that all plumbing fixtures, from the kitchen sink, to the bathroom, to the laundry room, are all in a straight line along the same exterior wall. Thus, all water lines, when moved indoors, can run along a single exterior wall.

If you find that, because of your home’s floor plan, running water lines indoors will involve running lines across a floor, a doorway, or a hallway in some places, should you abandon this project? Not necessarily. There are several possible solutions.

If water lines must cross a hallway or doorway, they could be covered with cable covers of the kind used to protect electrical cables.

Another solution would be to run the CPVC pipes vertically up a wall, then across the ceiling, and then down the opposite wall. Your plumbing supply store sells little semi-circular brackets for fastening CPVC to walls and ceilings--or for holding it in place in general. Lines run up walls and across ceilings are likely to be less noticeable (and troublesome) than if run across floors.

If coverings for running lines across floors must be used, your decision about going ahead with this project will depend on how big of a problem the frozen pipes are for you. Would it be worth it to you to have something a little unusual going on with the floor? Would you be willing to do an extra bit of work to cover these lines running across a hallway or doorway in such a way as to make the end results look fairly normal, or even rather attractive?

I solved this problem in my house by laying flooring of plain old two-by-six lumber. In some places water lines crossed the floor, but they were laid between the two-by-sixes. Then the lines were covered with a piece of thin lumber. Yes, there is a small bump in the floor, but it doesn’t look at all weird. Such a floor will not only look really nice when stained and varnished, it will also provide insulation and keep your floors from being cold.

This type of flooring will be kind of uneven and should be smoothed with a grinder before finishing. The reason you use a grinder to smooth it is because it is screwed down with metal screws, and a grinder to have no problem with sanding over these screws.

Or maybe you would be okay with laying two-by lumber on each side of the lines and covering them with a thin piece of wood. It may even be possible to locate this arrangement where it seems to make sense.

3. Drill holes in interior walls as needed and shown in your diagram.

Next, make the needed holes in interior walls, as shown in your diagram of the routing of the pipes. Think a little bit about the probable location of electrical wiring before you drill. It is very unlikely that electrical wires are running inside the wall at floor level, since that is not where they are supposed to be.

4. Calculate the materials you will need to lay water pipes above the floor.

Figure out how many feet of CPVC pipe you will need, and also figure out (as best you can) how many CPVC fittings (Ts, elbows, and straight couplings) you will need. Then go out and purchase the necessary materials, including CPVC glue and CPVC primer/cleaner. Ask for help in the plumbing aisle if you are unfamiliar with any of these materials.

You will also need heat tape and some pipe insulation for the short line under floor, as well as duct tape, to tape it in place.

One thing I should mention to people who have not done a lot of plumbing: Do not expect that you have figured all this out perfectly correctly, or that there will be no waste from bad cuts. It is also easy to come up short on your couplings, since there can be twists and turns you had not planned for.

One of the first things I learned about plumbing, from the plumber’s daughter who taught me, is that couplings (Ts, elbows, and straights) should be bought in handfuls. They are cheap, and you will likely need a lot more than you think.

The second thing that a person learns about plumbing is that it is very unlikely that you will figure out the needed materials to a gnat’s eyebrow, so that you need only make one trip to the hardware store. It is best to expect to make two or more trips. Try not to allow this to aggravate you; that’s just the way plumbing is.

There is an old adage about this: “Plumbing doesn’t happen without cussing.”

5. Find all the places where the hot and cold water lines come up through the floor. You are going to cut them—all but one, that is—but not yet.

Find all the spots where plumbing lines are coming up through a hole in the floor. You may want to mark or label them so you can tell at a glance which are hot-water lines and which are cold-water lines. Hot-water lines are supposed to be on the left, and cold-water lines on the right.

Now you are ready to begin.

6. Turn off water to the whole house at the main shut-off valve.

Before you begin, turn off the house’s water at the main shut-off valve. Pay careful attention to the location of the main shut-off valve.

The next step is to cut the plumbing lines where they come up out of the floor. But before doing this, you need to do two things.

7. Run water from house faucets until they stop running and the lines are dry.

Run water from one or more faucets in the house until it stops running and the lines are (relatively) dry. They will never be completely dry. However, if you begin cutting lines without running most of the water out of them, you will be cutting lines that still have pressure in them, and you will get an unwanted shower.

Any time you are doing plumbing work that involves cutting lines, always run the lines dry first.

8. Look at the main shut-off valve. Do not cut below it. Do not cut above it, either.

You have already located the main shut-off valve. DO NOT CUT BELOW IT! If this shut off is located at your hot-water heater, the line from it will run into your hot-water heater, so do not cut above the main shut-off valve, either. This line is already inside the house and above the floor, right? Since it’s already where you want it, there is no need to move it and hence no need to cut it. (See Figure 4.)

If the main shut-off valve is under your sink, you will see a similar arrangement of pipes. If you water lines are under your floor, then obviously the cold-water line coming from the shut-off valve will dive back under the floor, just as it does in Figure 4, next to the hot-water heater. See how the cold-water line next to the hot-water heater also dives back under the floor after branching off at a point past the shut-off valve.

Your objective is to cut this line where it goes under the floor. Figure 4 shows where to make the first cut in the hot and cold water lines.

The places to cut are the slanted green lines. Of course you will want to cut lines straight across, and not at a slant.

As you can see in Figure 4, below, you will NOT need to make any cut in the cold water line with the main shut-off valve on it.

If you were to make a cut between the main shut-off valve and the water service line coming from the curb, water would gush all over the place, and the only way you would be able to shut it off would be to use the shut-off at the curb-side meter (hopefully you have a shut-off tool) or call the water company to shut it off.

In Figure 4, I have designated the place where you should NOT cut the line in a hot pink color. The green lines show where you SHOULD cut.

Figure 4
Figure 4

9. Cut all other lines that pass through the floor.

In Figure 3, I’ve shown how lines pass up through the floor, branching off the hot and cold water lines that are under the floor in the crawl space.

What you are basically going to do, working from inside the house, is cut all these lines that come up through the floor. You will need to cut each of these lines just a little above floor level. Don’t cut too close to any coupling. Try to leave at least an inch of CPV pipe sticking out from the nearest coupling. You have to have something to glue the coupling to that you will glue the indoor line to.

When you are done cutting, the lines under the floor will just fall free and land on the slab at the bottom of the crawl space. If you so desire, you can crawl under there and remove them, so as to keep your crawl space tidy. Or, since your crawl space wasn’t tidy to begin with and you will never be crawling under there again, you could allow the present whereabouts of you old plumbing lines to slip your mind.

Oh wait! Actually, you will be going into the crawl space one last time. But we will come to that later.

10. Install new water lines indoors, according to your diagram.

You have now come to the pleasant and peaceful part of the job. This is where you measure off lengths of CPVC, cut to the right size, and glue them together.

Before you begin cutting the new water lines and sticking them together with Ts, elbows, and straight couplings, here is a bit of common-sense advice: Begin by putting everything together without glue. Once you have a good part of the cold water line assembled and you are sure everything fits just right, then you can go back and glue it.

If you do it this way, there will be no mistakes. This part of the job is actually kind of peaceful, pleasant, and relaxing. Work methodically, so that you don’t forget to glue one of the fittings.

Use glue and primer/cleaner according to the instructions on the cans.

You may want to begin with the cold-water line. It will save confusion to begin at the beginning of the cold-water line—that is, right where it first comes into the house. We will assume it comes in at the hot-water heater. You have already cut the cold water line where it goes back under the floor.

This piece of pipe is just kind of hanging there—as are all the other places where you cut the lines at floor level. Attach an elbow to the bottom end of this pipe. You can now attach a piece of CPVC pipe (cut to the length you need) to the other end of the elbow.

Now extend the CPVC pipe to the next place where the cold-water line needs to be attached to a plumbing fixture. Maybe you will have to run pipe around corners or through walls to get to it, and maybe you won’t. Just put together CPVC pipes and fittings using the appropriate couplings until you reach the plumbing fixture that is next in line. The pipe that supplies it should be hanging down where you cut it off. Put a T coupling on it (upside-down). Your piece of CPVC pipe, which you cut to the right size to run to this fitting from the previous one, can be inserted into one side of the T coupling. The other side of the T coupling will receive the next piece of CPVC pipe.

So you just keep going, extending the new cold-water line from one plumbing fixture to the next. Be sure that you are hooking up the cold water side of fixtures to the cold-water line.

Customarily, the cold water is on the right side of sinks, tubs, and showers. If this is not the way it was originally, this is a good time to do it in the “right” (or at least customary) way.

When you have put the last coupling on the last fixture in line, you are done with the cold-water line. Now you can go back to the hot-water heater and do the hot-water line the same way.

11. Wait for CPVC glue to dry.

Once you are done, you may want to inspect all the lines before you turn on the water. You may also be wondering how long you should wait for the CPVC glue to dry. This will depend on the brand of CPVC cement you are using. Check the directions on the can.

In general, it is best to wait 24 hours for glue to dry before turning on the water. There. I said it. Nevertheless, I do have to tell you that most people don’t wait that long. While you are waiting for the glue to dry, you can research the question on the internet. You will find that opinions vary.

How long do I wait for CPVC glue to dry? At least one hour. After you have fully investigated this interesting question, use your own judgment.

12. Turn the water back on and check for leaks. Repair any leaks and wait for the glue to dry again. Then turn the water back on and check for leaks again.

Once you are satisfied in your mind that the glue has dried, turn on the water back on at the main shut-off. Re-inspect all the lines, to make sure there are no leaks. If you forgot to glue a spot, it will be easy to notice the leak. In fact, the coupling is likely to pop loose and cause a bit of a geyser.

There is no reason to be dismayed about this. Remember: This is plumbing. Mishaps like this are a pretty regular thing. This is not electricity. When you make a mistake, you get wet, not electrocuted.

If there is a leak (or geyser), simply turn off the water at the main shut-off valve and glue the line together where you probably missed a spot. Wait for the glue to dry again, and then turn the water back on and see what happens.

13. Remember, there is still some water line under the house. Wrap it with heat tape and insulation.

If your water lines running under the house were freezing from time to time, that little stretch of line that is still located under the house is still susceptible to freezing. If it freezes, you will have no water supply to your house.

Wrapping this line with heat tape is not a big job. It is a pretty short line. After you’ve wrapped it with heat tape, cover it with pipe insulation. Both the heat tape and the pipe insulation need to cover the line from where it emerges from underground, up to floor level. Secure the pipe insulation with duct tape, so it doesn’t come off. Plug in the heat tape.

14. Cover the exposed indoor plumbing lines with the material of your choice, so they are out of sight and look nice.

Under item number 2, “Decide how you will cover the pipes,” you will have selected one or more materials to do the cosmetic part of this job. Luckily, this part of the job can be done in a more leisurely way, since you are no longer under pressure to get the water running again, so people can flush the toilet.

When you’re done, you will not only have frost-free water lines, but the indoor lines will be so well disguised that no one will be able to notice them.

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    • blueheron profile image
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      Sharon Vile 3 years ago from Odessa, MO

      You are much more alert than me. I was oblivious till I was 50. I know you rmember the old days, when Bobbi was showing me how to fix leaks, and we'd drive all over the place looking for an elusive male adapter, and come home with handfuls of "plumbin' fittin's"--loaded for bear. Good times!

    • goldenrod profile image

      goldenrod 3 years ago

      Great article! Super informative and funny. Makes me wish I was helping you all those years you were crawling under the house, while I sat on the couch watching TV after school, wondering why the heck you were down there. Funny how oblivious I was when I was a teenager.

      Maybe I should get into plumbing.

    • blueheron profile image
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      Sharon Vile 3 years ago from Odessa, MO

      Calling Don Bobbit! I KNOW you moved all your lines indoors years ago.