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Installing a Whole-House In-Line Water Purifier

Bert spent 25 years working as a home-improvement and residential construction contractor in central Florida.

Get cleaner water by installing a water purifier.

Get cleaner water by installing a water purifier.

Why You Should Consider a Water Purifier

A whole-house, in-line water purifier removes sediment and contaminants from a home's water supply. This type of water purifier, often called a whole-house water filter, mounts on an interior wall and taps into the home's main water pipe before the water reaches any of the home's faucets, water heater, or ice maker. It does not replace a well system's water softener. Without a water filter, contaminant buildup coats the inside of the home's pipes and negatively affects any water-using appliance's performance. Installing a water purifier can greatly extend the life expectancy of any water-using appliance.

What to Consider Before Installation

A typical whole-house water purifier has three parts: the manifold, the filter assembly and the filter. Most whole-house water purifiers use canister-style filter assembly. The filter slides into the canister. The canister screws onto the bottom of the purifier's manifold. The amount of contaminants removed depends directly on the type and age of the filter used. Several different grades of filters are available; ranging from a basic filter that only removes rust and sediment to the highest grade purifier filter, which removes some bacteria and parasites.

Before buying a whole-house water purifier, compare your home's piping size with the manifold's ports. The manifold must have ports at least the same size as the pipes. Most homes use 3/4- or 1-inch water pipe. Water purifiers with smaller ports choke down the water flow. A larger port simply requires a bushing or other reducing fitting.

Always use the water flow directional indicators as reference during installation.

Always use the water flow directional indicators as reference during installation.

Mount the Whole-House Water Purifier

Where you mount the whole-house in-line water purifier depends on the layout of the home's plumbing pipes and water heater. Ideally the water purifier will connect to the home's water supply between the building's main water valve and the first branch pipe or water-using appliance. Many homeowners find the best place to tap into the water pipe is near the water heater. The best location will have easy access for future filter maintenance.

Open the filter assembly's package and examine the system. Locate the arrow on the assembly's manifold. The arrow indicates the direction the water flows through the system. Keep this arrow in mind while planing the water pipe's route from the main pipe to the purifier's mounting location.

Attach the water purifier's mounting bracket template, if supplied, to the wall with masking tape. If the purifier does not have its template, hold the whole-house in-line water filter's mounting bracket against the interior wall and trace the mounting bracket's screw holes on the wall. Some purifiers have mounting holes in the manifold; others have a separate mounting bracket. Set the mounting bracket aside.

Drill pilot holes in the wall, using the marks on the wall or template as a guide. Insert the proper anchor, if used, into the pilot hole. Drywall-covered and concrete block walls require anchors. Position the bracket's screw holes over the pilot holes or anchors. Attach the water purifier's bracket to the wall with the appropriate screws.

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Prep the ends of the pipes for the whole-house purifier's plumbing connections.

Prep the ends of the pipes for the whole-house purifier's plumbing connections.

Connect the Water Purifier to the Home's Water Pipe

  1. Double check the pipe route and verify all pipes and fittings have room. Disconnect the electricity to the water heater and turn off the water supply. If the house uses a well pump, turn off the pump motor's circuit breaker. If the home connects to a city water meter, turn off the main water valve. Open one of the home's hose bibs and relieve the water pressure from the pipes.
  2. Remove a 5- to 6-inch long section of the main water pipe between the first T-fitting and where the pipe enters the home's interior, using the appropriate cutting tool. Leave at least 2 inches of clean pipe on each side of the cut. The two inch section of pipe leaves plenty of room for the plumbing fittings needed to connect the water filter.
  3. Attach a 90-degree elbow to the main water pipe entering the home, keeping the elbow's discharge port facing the water purifier's mounting location. Run a pipe from the elbow to the in-line water purifier's intake port, keeping the pipe tight against the wall. The type and amount of fittings and pipe required depends on the purifier's mounting location and the type of pipe used. If using PVC or CPVC pipe and fittings, coat the fittings and pipe with a primer before applying the PVC cement. The primer softens the pipe and fitting's mating surfaces, which helps the cement bond. If using PEX or copper pipe and fittings, remove all debris and corrosion before making the connections. Many homeowners choose to use push-on plumbing fittings when working with CPVC, PEX or copper pipe. A push-on plumbing fitting does not require a torch and solder, glue and primer, or rings and a clamp tool. The arrow on the top of the water purifier points toward the discharge port.
  4. Connect the in-line water purifier's discharge port to the end of the two-inch-long pipe connected to the Tee-fitting. Attempt to layout the discharge piping so that it does not cross over the intake piping and rests tight against the wall. If the discharge pipe must cross the intake pipe, use fittings to bridge across the intake pipe's surface.
  5. Secure each pipe against the wall with two-hole hanging straps. The straps will keep the pipes from vibrating. Place a strap every four feet along each long section of pipe, as needed.
  6. Lubricate the whole-house in-line water purifier's canister O-ring with a waterproof and food-safe grease. Place the water filter in the canister. Hand tighten the canister onto the water purifier's housing, turning the canister clockwise. Slip the canister wrench, if applicable, over the end of the canister and turn the canister until it is tight.
  7. Turn on the home's water supply. Turn on both the hot and cold water sides of each faucet. Leave the faucets on until all of the air in the water pipes escape.

How to Maintain It

Check each plumbing fitting for water leaks and repair as needed. Usually the best way to fix a leak is simply to replace the leaking fitting. Band aid-type patches do not hold up well long term and almost always fail at the worst time. If the threaded fitting connected to the whole-house inline water purifier leaks, cut the pipe about 1 inch from the threaded fitting.

Remove the threaded fitting from the water filter manifold and clean the thread sealant from both the fitting and the manifold. Apply a thread sealant paste to the male threads. Thread sealant paste is a foolproof way to protect and seal plumbing threads. Simply fill the first third of the male fitting's threads with the paste. Tighten the fitting with a wrench and reconnect the pipe with a coupling. Turn on the water and retest the system.

Once the whole-house water purifier passes a leak test, flush the air from the pipes in the house. Turn on the faucet furthest from the water filter, which is often a hose bib located outside. Keep the faucet on until the faucet stops spitting air. This may take several minutes. Repeat this at each faucet, working toward the whole-house water purifier. Usually a homeowner with some plumbing knowledge and skill can complete the entire installation process in less than three hours, in many cases less than one hour.

Water Purifier Maintenance

Following the water purifier manufacturer's maintenance instructions will keep the home's water supply contaminant free. Normally this only requires filter replacement and O-ring lubrication every three to six months. Applying a thin layer lubricant at every filter change will greatly extend the O-ring's life.

Before applying lubricant, inspect the O-ring for nicks or badly deformed areas. Replacement canister O-rings are available online. Some local hardware stores carry a large O-ring assortment and will carry the large O-rings needed. Choose the O-ring that exactly matches your canister size; an improperly sized O-ring will leak.

Use a filter wrench to loosen stubborn canisters. The large open end of the wrench slides over the end of the canister and fits into grooves near the manifold. Gripping the canister near the manifold limits the chances of damage.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2012 Bert Holopaw

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