Skip to main content

Closing an Inground Swimming Pool? How to Winterize a Pool for an Easy Spring Opening

The finished product.

The finished product.

How to Winterize an Inground Swimming Pool

Closing an inground swimming pool is a lot more challenging than opening an inground swimming pool. The challenge is removing all the water properly from the pool equipment and plumbing as well as winterizing it for the freezing temperatures that are on the way. If you winterize your pool properly in the fall, a spring opening will be a snap, and you will be the envy of your neighborhood pool owners.

I took a step-by-step approach with many pictures so I could walk you through the process as much as possible without physically being there to help you. As I closed my pool this fall, I took very detailed pictures to help me animate the procedure so you won't run into any problems. If you have any problems or questions, just shoot me a comment, and I will answer it ASAP because, at this time of the year, time is of the essence.

Step 1: Preparing for Winter

First and foremost, your pool needs to be totally clean and the pH, alkalinity, hardness, and chlorine need to be set to their ideal levels. This is the most important step because if you close a dirty pool, it will only get worse throughout the winter. So clean it, set it, and forget it!

Step 2: Buy a Winterizing Kit

When you purchase a winterizing kit, buy one that will winterize the amount of water you have in your pool. If you buy a kit that is too small, it will be wasted money, so know your pool's water capacity and buy the right kit.

I had to buy two kits this year because the company I buy my winterizing kits from stopped selling the large kits for 25,000-gallon pools. You'll aso want to purchase a disposable floating chlorine dispenser that will float around your pool when the pool isn't frozen- it will keep the water clear, and it helps kill any algae that attempt grow on the warm spring days.

Step 3: Start Adding the Winterizing Kit

It's best to follow the instructions on the winterizing kit; that's why they're there. You need to add the PhosFree to your pool water first to remove any phosphates in the water; by removing the phosphates in your pool water, you will stop the growth of algae throughout the winter. Add the PhosFree a week before closing your pool; just pour it into the filter and let it do its thing. I recommend starting the process one weekend before closing your pool.

Step 4: Add the Rest

Start by adding the bottle of metal free to the pool water, just sprinkle it across the top of the water, do not add it to the filter. The metal free will remove any damaging metals in the pool water, this will prevent any stains or water discoloration in the off-season.

At this point, your pool water should be clean, free of metals and phosphates, the chlorine level should be almost perfect, and your pH, alkalinity, and hardness levels should be at the ideal levels. Now it's time to drain the pool.

Step 5: Lowering the Pool Water

According to some winterizing kits, you should lower your water level about 18 inches from the top of the skimmer. An easy way to determine if the water is low enough is to lower it to the bottom of the return jets/ lines. When you lower the water level below the return lines, it allows the water to drain from them as well, so lower the water to just below the return lines (see the pictures for details).

Use the pool pump to lower the water level, turn the diverter handle to backwash, then turn the inlet lever to draw water from the bottom drain of the pool and not the skimmer. This will allow you to lower the pool water well below the skimmer without sucking air into the filter. While the pool water is draining, start removing the jet nozzles on the inlet lines, skimmer basket, ladder, and handrails. If you have a safety cover, start pulling up the anchors on the pool deck and start unwrapping the pool cover that you have in storage.

Once the water is below the return lines, you can shut off the pump. But before you shut the pump off for the winter, you need to suck the remaining water from the skimmer. The best way I found to suck the remaining water from the skimmer is to use the pump one last time. When you're ready to stop pumping water from the bottom and the water level is where you want it, turn the lever on the inlet pipes to skimmer until you hear the pump suck air, then turn off the pump, but leave the inlet lever on skimmer.

Now is a good time to add antifreeze to the skimmer; the water level should be low enough in the skimmer so that when you look down into the skimmer you cannot see any water in the pipe, if there is no water in the pipe, add your pool antifreeze, about 1 quart to 1 half gallon. Install the gizmo with Teflon tape wrapped around the threads and then add about 1 quart to 1 half-gallon of antifreeze to the skimmer housing so that it surrounds the gizmo.

The gizmo is installed for two reasons; one is to stop water from reentering the skimmer lines during the winter and two, it is air-filled, so that if water does enter the skimmer and freezes, the ice will expand and crush the gizmo and not split or crack your skimmer housing.

Once the gizmo is installed and the antifreeze is all set, take the skimmer cover and wrap it in a plastic bag; just take a plastic bag and put the skimmer cover in it, then wrap it so that the top of the cover is wrapped tight and the remaining part of the bag is on the underside of the cover. Next, install the skimmer cover on the skimmer (see pictures)- this plastic bag will help keep out rainwater during the off-season.

Clean Your Pool Steps Before You Close It

Install an air line fitting on the bottom of your filter basket housing, remove the drain plug and install the air line fitting.

Install an air line fitting on the bottom of your filter basket housing, remove the drain plug and install the air line fitting.

Attach an air line from your compressor,  remove the water from the return lines, make sure the diverter handle is in the filter position.

Attach an air line from your compressor, remove the water from the return lines, make sure the diverter handle is in the filter position.

Step 6: Blow Out the Lines With Compressed Air

Blowing out the lines sounds daunting, but it's quite simple. On the bottom of the basket housing at your pool pump, there is a little plug.

  • Remove the plug, and install an air line nozzle so you can attach an air line easily (see pictures for more detail). Drain the basket housing of water, drain the pool pump from the bottom drain and unscrew the vent at the top of the pump to allow air to enter the top of the pump and let the water drain faster out of the filter.
  • Once the pump and the filter basket housing are drained, reinstall the drain cap on the filter, the vent cap, and install the air line fitting to the bottom of the basket housing. Clean out any leftover chlorine in the self chlorinator. Set the diverter handle to filter and add compressed air to the filter at the air line fitting.
  • Watch the water drain from the return lines; when the water stops coming out of the return lines, shut off the compressed air and cap the lines with special caps designed to keep water out during the off-season. These caps have rubber o-rings, but I like to use Teflon tap on the threads for added protection; I also add Teflon tape to the threads of the gizmo for added protection.

Step 7: Add Pool Antifreeze to the Pump

The pump and filter should be drained by now, and the pump basket housing should only have a little water in it; if you think there is still too much water in the basket housing, just scoop it out with a plastic cup.

  • Add about 1/2 gallon of pool antifreeze to the pump basket housing and reinstall the cover. Add pool antifreeze to the self chlorinator, about 1 half gallon, then reinstall the cover. You should only need about 2–3 gallons of pool antifreeze to close the pool unless it's a huge pool; I am basing the capacities on a 23000-gallon pool.
  • Place the handle of the diverter valve in a neutral position between filter and waste, or something like that, just don't leave the lever in one of the designated positions because there is still water in the diverter, when you put the handle in a neutral position it will allow the water to freeze and expand without cracking something internally on the diverter valve (see picture).
  • After the pool pump has been winterized, remove the drain cap from the bottom of the sand filter or DE filter just to finish draining the water from inside the tank. The filter is saturated with water, and I like to let it drain thoroughly so I will leave the drain cap off for 24 hours. If you have a filter cartridge, remove the cartridge and power wash it, then store it for the winter.

Step 8: Installing the Pool Safety Cover

By now, you should have all the pool cover anchor's popped up the cover should be ready to install. A safety cover has an upside and a downside. When installing your safety cover, you will notice that the downside has hard plastic belts stitched into the cover to protect the cover from rubbing on the concrete during windy days, it also allows the cover to stretch without damage when snow and ice build-up on top of the cover.

The cover is made to stretch like a trampoline; there are springs where the cover attaches to the anchors, so when the snow and ice build-up on top of the safety cover, it will stretch to the top of the water. After the ice and snow melt in the spring, it will spring back up, and the debris will dry and blow off.

  • Start the safety cover installation by rolling out the cover on the pool deck or your lawn, find the end of the cover that goes over the stairs, and place the cover near the edge of the pool so you can slide the cover over the pool easily. Slide the spring covers over each spring as you attach them to the anchors; otherwise, they may fall off into the water when installing the cover. Start by attaching the two springs on each end in the center of the cover, the long way (see pictures).
  • Use the metal pole that came with the pool cover to install the springs onto the anchors. If the cover has no spring installation tool, you can use a 3/4 metal pipe. Slide the tool into the loop end of the spring, put the pipe over the anchor, move the pipe straight up and down over the anchor and use your foot to slide the spring onto the anchor.
  • Once the cover is supported in the center the long way, find the center springs in the center the short way and attach them as well. Installing the cover doesn't have to be done perfectly; it just prevents the cover from filling up with water, making the installation easy.
  • From there, just install the remaining spring covers and attach the remaining springs to their appropriate anchors. Be sure that the straps that attach the cover to the springs are lying flat on the concrete and not twisted, it looks better, and there is a hard plastic strip stitched into the strap to prevent premature wear.

I use to remove the pool light for fear of it cracking from the ice pushing against it, but now I leave it in. I have left in the pool for over 6 years and have never had a problem. It is personal preference, but if you want to remove the pool light, there is one screw at the top of the light, and the bottom of the light slides into a holder.

Just remove the top screw and tilt the top of the light out; the bottom of the light will slide out of the holder. The pool light wire should be long enough to store the light inside of the diving board, which is a normal practice of the pool companies if the light is removed.

Your Pool Is Ready for Winter

So that's it! Store your ladder, handrails, and pool accessories for the winter, I use a bucket to store all the baskets, nozzles and whatever else that goes to the pool all in one place so when spring comes, you can find everything easily. If you think I may have left out a step or you have a question, just ask, and I will get back to you asap. Most people won't attempt closing an inground swimming pool for fear that they might do something wrong.

Once you close a pool once, it will become easier each year, and it will save you around $200–$300. Plus, you will have peace of mind that it's done right. I had my pool closed once by a local pool company, and my pool was dark green in the spring; it took me two weeks to clear it up and a lot of chemicals. Needless to say, I have done it myself since then.

More About Pools

  • I Had the Worst Pool Algae This Spring
    The pool algae this spring was the worst I had ever seen, I even used a winterizing kit, and it was still dark green, with black algae. The chemicals and pool filter were a losing battle, and the algae were winning.
  • How to Change the Sand in a Pool Filter
    If you want to change the sand in a pool filter, here are the step by step, easy to understand instructions. I'll show you how easy it really is.
  • How to Open an Inground Swimming Pool
    What is my secret to clear pool water when opening my inground pool in the spring? When the cover comes off, the pool water is crystal clear and all the debris has settled to the bottom. Most pool owners ask “How is this possible?”

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


Eddie Carrara (author) from New Hampshire on October 15, 2019:

Hi Mark,

I close all opening leading into the pool with plugs and gizmos because most likely the water will rise throughout the winter and fill the lines again possibly freezing and causing damage. Let me know if this helps.

Mark in michigan on October 10, 2019:

For the winter do you close the drain and leave the Skimer open or close it as well

Eddie Carrara (author) from New Hampshire on October 08, 2019:

Hi Marc,

I usually lower the water to just under the return inlets.

Merc Pusateri on October 08, 2019:

Closing inground pool with sun shelf approximately 15 inches below water line. Should I drain pool below the shelf? It also has a bubbler.

Eddie Carrara (author) from New Hampshire on October 02, 2019:

Hi Diane,

It will usually take the entire weekend to close the pool, I actually start adding the winterizing kit a few days before the weekend so the water is perfect before closing it down. Be sure to add biodegradable antifreeze to all the lines and skimmer. It's not a bad idea to turn off the breaker at the service panel so the pump isn't accidentally turned on during the winter months, especially if you have a timer.

Diane Hitchcock on October 01, 2019:

Thank you Eddie! Wish us luck, this is the first time in 11 yrs. we are closing ourselves. We live in Delhi, NY and our price for pool closing went up to $411 this year! It's Crazy!!!

Eddie Carrara (author) from New Hampshire on September 30, 2019:

Hi Diane,

Yes, you will need to drain it completely and turn off the gas if you live in an area that freezes.

Diane Hitchcock on September 30, 2019:

What about the pool heater do you have to do anything to winterize it?

Eddie Carrara (author) from New Hampshire on July 24, 2019:

Sorry to hear that Liz, but you can stop at the natural hot springs along the way :) Keep writing about your journey as a full-time nomad, the stories should be very interesting :)

Liz Elias from Oakley, CA on July 21, 2019:

Alas, but the window for having a pool is closed. I don't have the income to qualify for such a loan, and besides, I'm preparing to sell the house and hit the road as a full-time nomad.

Eddie Carrara (author) from New Hampshire on July 21, 2019:

Hi Liz,

I hear the same thing, "it's a lot of work and the cost is too high". I have had 2 inground pools, one above ground, and one 6 person hot tub, the hot tub was by far the most difficult to maintain and I didn't enjoy it much between the maintenance lol. The inground pools were super easy, basically set the chemicals and forget it if you do it right and use the proper chemicals.

We only partially drained the pool for winter and you can either run a hose into the woods or drain it into the street, the pool water is basically drinking water if the chemical levels are correct and won't harm vegetation or animals.

I wish you could have enjoyed something you wanted so bad, I'm looking into my second above ground pool but I'm thinking about burying half of it and build a patio on one side if I do I'll create a hub on my experience :)

Thanks for sharing your story and don't give up hope, there's still time for a pool :)

Liz Elias from Oakley, CA on July 12, 2019:

I've wished for a pool ever since I can remember. Growing up in San Francisco, however, the climate was not right, and my parents didn't want to move.

When I finally managed to move to my current location, there was ample space for a pool, (property is just under 3/4 of an acre), but my husband, who'd had pools before, said "they're a lot of work plus add about $200 a month to your utility bill!" I disagreed, saying if I put in a pool, I'd put the pool equipment on solar--off the grid, then use a pool maintenance company! LOL

In the end, it was not to be for many other reasons, and at this point, I don't think we could have had a pool anyway, because where would we drain it? We're not on city sewer, but on a septic tank system! :-(

We had a couple of above-ground pools over the years that we'd set up for summer, and when it was time to drain and put them away, it was only a matter of deflating the top ring and leaning on the side, letting the water pour out onto the ground--we have very sandy soil, so it didn't travel far!

But, they weren't really much fun--not big enough to swim--only splash around.

All that said, I did find your article interesting--and if we had had a pool, I don't think it would be necessary to fully close the pool for winter--we don't get snow and ice here. ;-)

Eddie Carrara (author) from New Hampshire on October 11, 2018:

Hi Dawn,

I alway use the "In The Swim Kit" I have a 22k gallon pool and usually have to buy 2 kits.

Dawn on October 09, 2018:

What pool closing kit do you purchase? First time owners of a pool here =)

Eddie Carrara (author) from New Hampshire on October 31, 2017:

Hi Tom,

I recommend checking with the manufacturer or checking the label on the bottles if you have any left.

Eddie Carrara (author) from New Hampshire on October 31, 2017:

Hi PeachWillow,

If you live in a warm climate where the temps don't get below freezing, yes, the closing instruction will vary a lot.

PeachWillow on October 30, 2017:

When closing an inground pool, do your instructions vary if we decide to NOT add pool anti-freeze?

Tom Homeier on October 26, 2017:

I didn’t use my pool this year and I wonder if the pool line antifreeze will still be good and make it through two winters? I vacuumed the lines before I capped it and used 7 gallons on pool line antifreeze.


Tom Homeier

Eddie Carrara (author) from New Hampshire on September 28, 2017:

Hi Paulette,

The air line fitting is a standard fitting that you would hook to an air tool or air hose.

Once you blow out the skimmer line there will still be some water in the line but it will be down about 5-6 feet and you probably won't be able to see it, I add about a half gallon down that skimmer line, install the gizzmo, then add the rest of the antifreeze to the skimmer basket. Fill the basket on the pump with antifreeze and don't worry about filling the lines coming into the pump from the pool, one comes from the bottom and one comes from the skimmer. When blowing out the skimmer line and bottom drain line, the water levels should be below the frost line. Let me know if you have more questions.

Paulette on September 24, 2017:

Hi. Thanks for the great instructions. However; I have 2 questions...

1. Where do you get an air line fitting to fit the bottom of the filter basket? Mine filter has a black screw in “key” or knob” and the opening is quite large and has treading?

2. You said to fill the filter basket and bromatator, in my case, with anil-freeze, you didn’t explain how you get the anti-freeze down and into the return pipes? Do you turn the pump on for a couple seconds to move the anti-freeze into the return pipes? Thank you again for your help

Eddie Carrara (author) from New Hampshire on September 21, 2017:

Hi Amanda,

I recommend still winterizing the filter and lines, but as far as the pool water goes, if you're not going to reuse it, let it get green.

Amanda on September 17, 2017:

Hi! We will be replacing our liner for our in-ground pool next spring. We were going to drain the pool to the level of the deep end, where the shallow end meets. Do you still recommend using winterizing chemicals? In the spring, we are just going to drain the pool anyways. Thanks!

Eddie Carrara (author) from New Hampshire on September 09, 2017:

Hi Regina,

Just make sure most of all the water is drained for the lines and use non-toxic environmentally safe antifreeze in the lines and filter.

Eddie Carrara (author) from New Hampshire on September 09, 2017:

Hi Tammy,

No just cover the pool, the snow and rain from winter will fill it back up naturally.

Regina on September 07, 2017:

Thank you so much for this detailed article. I can't get on the pool company's schedule for another 6 weeks so am going to attempt this for the first time myself this year.

Tammy on September 07, 2017:

Do you raise the water level back up after plugging and anti freeze ..

Rocky B on August 28, 2017:

what size air compressor is needed?

Mike M. on August 11, 2017:

I always have opened my pool but paid a pool company to close. After reading your step by step instructions I'm ready to close it myself. Thanks, Mike

Eddie Carrara (author) from New Hampshire on November 10, 2016:

Hi Stephanie,

Not really, but you can rent one pretty cheap. Let me know if you have more questions.

Stephanie Raynor on November 10, 2016:

What if I don't have an air compressor to blow out the pump? Is there an alternative?

Eddie Carrara (author) from New Hampshire on January 16, 2013:

Hi Robert,

When you work in the automotive field, you learn to do everything yourself, and usually just as good, if not better than the professionals. (because it's my stuff, lol) There a very few jobs I will hire someone to do for me, and if I do hire someone, I watch every detail so I can do it myself the next time :) Thanks for the feedback, I appreciate it very much.

robert1980 on January 16, 2013:

Not bad that's pretty much right on.I'm a Supervisor/Swimming Pool Technician.Very detailed by the way.

Eddie Carrara (author) from New Hampshire on January 07, 2013:

Hi swimfan,

Just trying to help my fellow pool owner, a lot of pool owners will pay someone to close their pool, costing them over $250. It's really not that hard, plus you have a better chance of having clear water in the spring if you do it yourself and do it right :)

Thanks for the comment.

swimfan from United States on January 07, 2013:

Wow, really detailed, step-by-step information. I appreciate the effort it must have taken to put this article together.