Why Do You Leave Water in Your Pool for Winter?

A lot of people who have pools are now starting to search for insight on how to close their pools correctly. Any pool closing checklist or resource will tell you to only lower the water below the skimmer level and the jets so that all of the plumbing lines are clear and don’t face the risk of freezing and bursting. Each of these different resources also tells you not to drain the pool completely unless you are taking it down for storage if it is a small pool that is easy to set up and tear down. What about larger pools, though?   Why leave water in them at all?  It will just be bad next spring, after all.

Actually, that’s not really the case. If you drain a pool entirely, you are putting the whole liner at risk for rips, tears, and other damage from debris throughout the winter months, not to mention that the liner will dry out, shrinks and crack.  With some water left behind, you at least have something to stop the pool from getting torn up regardless of the winter weather that you are experiencing.  The pool cover that you choose will impact how much water you leave in your pool beyond lowering it to the skimmer lines, of course, so that’s something that you have to think about, as well.

Clean Water Protects Your Pool

The main benefit of leaving water in your pool is that it will be protected from a variety of situations and elements. People who live in deep freeze areas feel like draining the pool completely is the best option so that it doesn’t freeze all the way, but the right winterizing chemicals added to the water will actually help keep your pool safe during the long winter months. That way, when you go to open it up in spring, it’s easier to reopen and the chemicals are easier to balance because you made sure they were balanced before you closed up shop.

You’ll add things like chlorine shock, stain prevention, and algaecide to your pool before closing it for the winter. This will ensure that the water is as clean and safe as possible so that you can have an easier time reopening it next spring. This clean water is going to keep the liner intact and protect it from rips and tears, as well.

How Much to Drain

The standard is to drain your pool below skimmer levels so that you can clean out the plumbing system to avoid frozen, burst lines during the winter. If you have an in-ground pool, that might mean more draining. If your above-ground pool has a removable pump and skimmer system, just take it out and drain a little water so that there is room for expansion and contracting throughout the winter and then place the cover on.

Some people use air pillows to create an area in middle of pool to minimize ice damage to liner walls and skimmer.  If you do this, you will need to leave more water in your pool than others. Additionally, if you have drained a lot of water, you might want to choose a tight pool cover so that it is less likely to collect water and debris. Having a lot of standing water on your pool cover can lead to stress, rips, and damage to the cover as well as debris and dirty rain or snow getting into the pool that you worked so hard to clean.

Owning a Pool is Work

So many people think it’s fun to have a pool. It most definitely is. It’s also a lot of work, however, and you have to know what you are doing so that you can protect your investment. This isn’t a cheap toy to have around and you will likely spend thousands on maintenance and operations in the summer months. If you take the time to do the work correctly when it comes to closing your pool, you will be able to protect your investment and make the money that you have been spending worthwhile.

Another benefit of properly draining and closing a pool is that you will have an easier time reopening it when summer rolls around again. There is nothing worse than closing up a pool poorly only to spend weeks cleaning it and getting it ready for summer. If you do a little of the work now and make sure that you do it properly, everything will work out better for you in the end. Take the time to learn about pool ownership, including closing the pool and proper draining so that you can get the best results from your winterizing.

Some Pools Need Put Away

If you’ve got a small enough pool, such as the ones that they sell at superstores for just a few hundred bucks, you’re probably going to be tearing down and putting away the entire thing for the winter. These pools are great because they’re affordable, but they’re also not made to be permanent fixtures. You’ll have to check the manufacturer’s instructions to figure out how to close the pool properly and whether it can be left for the winter or not. The last thing that you want to do is leave it out without knowing better and wind up ruining it or having to spend a fortune when it comes time to reopen your pool.

Pool maintenance in the winter is really easy if you close your pool right. Whether that means draining some of the water before you cover it or completely tearing it down and putting it away depends on the pool that you have. Either way, you will protect your investment and get more from your pool ownership if you spend a weekend doing things the right way. When you make the decision to own a pool, you’re making a commitment to take care of it properly. That means spending a day or two every fall getting things ready for winter, and the sooner the better. Now that you understand more about draining and closing pools, it should be easy to get the process taken care of.



About Trey Collier

Grew up as a Military Brat. (Thanks Dad. Hats off to my Mom too as it took a special person to be married to someone in the military) Was a competitive swimming in high school and in college. 11 years was a Red Cross Volunteer, teaching kids & adults how to swim, do CPR, and first aid. Proud Dad of two beautiful girls.

17 thoughts on “Why Do You Leave Water in Your Pool for Winter?”

  1. Zequek Estrada

    I didn’t know there was so much work involved maintaining a pool. It makes sense if you want to protect your investment. I guess if you’re pool is tended to each day then the work wouldn’t be too bad.

  2. Stacey

    My small above ground pool was filled to about 6 inches below the skimmer at the beginning of winter. The person who closed it for winter put an too-big tarp over the pool and I believe as rainwater collected on the tarp displaced the pool water out the drain. Now I did drain the water on top of the tarp about a month ago and then came the snow & the deep freezes. Now it appears there is only maybe 12 inches of water inside the pool, the tarp is all the way down there & hanging on the edges of the pool frame. The water on top of the tarp is frozen solid. Is there anything I can do at this point to prevent the pool from suffering damage? Should I try refilling with the tarp on?

    1. Trey Collier Post Author

      Good Question Stacey. Let me see if I understand and correct me if I didn’t. Pool water was drained to just under skimmer! (Good…water shouldn’t be in skimmer to freeze and crack it) Oversized winter cover was put on top of pool water. Rain and snow melt added water above the cover….this water squeezed the pool water below cover up and out the skimmer drain (and hopefully it drained onto the ground and not into the pump/filer)

      1) If water under the cover plus water on the cover is still up near the skimmer in total (even if frozen), then you should have enough pressure inside the pool to counter the wind forces from the outside inwards.

      2) If the water under the cover has dropped to 12″ high…..and you pumped off the water on top of cover when it was liquid and the total water (above and below cover) is 12+ inches below the skimmer….this could be hazardous to the pool walls. In this case I would see what I could do the put water in under the cover (preferred) or on top of cover until the total is just under the skimmer.

      In either case above, continue to monitor the “Total” water level and keep it below the bottom of the skimmer.

      What bothers me with this is that the water on top will not normally push water below cover upwards and out the skimmer. Sounds to me more like there may be a liner leak and that should be addressed this spring.

  3. Barry Dixon

    I drained my pool about a foot below the skimmer but now it’s filled back up to an inch from skimmer. {Rain and melted snow} Should I consider drilling a hole through the ice and syphoning more water out?

    1. Trey Collier Post Author

      There are many reasons for above ground pool walls to collapse even when properly filled with water. Improper Foundation. – Rocks, sticks debris can cause holes in liner and leak water which then erodes the foundation causing the collapse. Poor Assembly – follow all manufacturers instructions make sure they are straight. Poor Maintenance Bolts become loose, corrosion issues. Treat then paint corrosion and keep everything tight. ICE Alone it won’t cause it to collapse, but if you move the ice around that may damage the seams or supports which when is thaws it could make it collapse.

    2. Phyllis

      Could not find leak in above ground pool. Now only about a foot water left. Winter coming? What to do? Can pool collapse if left this way?

      1. Trey Collier Post Author

        Yes It will collapse inward when the wind picks up. Above ground pool walls are engineered to hold water inside. They assume that there is water pressure pushing outwards so it resists against this force. Wind can collapse the walls inwards because there isn’t any water in the pool pushing back.

        If the water drained from the leak down to 12″ and stopped, then the leak is in a hole somewhere at the waterline. If you cant find leak, replacing a liner or calling a local pool person to find leak and put a patch on is cheaper than replacing your pool wall.

  4. adam

    I emptied my 17,000 gallon unground pool completely in anticipation of putting in new liner in spring….is this not a good idea? i live in new york and have a mesh cover on it for winter

    1. Trey Collier Post Author

      Well, I can’t really tell if you meant in-ground or on (above) ground with your “unground pool”. So I’ll try to answer for both possibilities.

      Bottom line is that NO it is NOT a good idea!

      Above ground pool walls are designed to push back inwards against the force of water in the pool. They have not been engineered to push back from outside the pool walls against the wind, and they wouldn’t need to when filled with water. So if this is an above ground pool, without water in it, a gentle breeze could collapse the pool walls inward and ruin the wall.

      In the case of an in-ground pool similarly the walls are designed to hold against the water in the pool. Soil when wet is capable of moving and it could collapse the wall inward without the water in the pool to hold it back.

      In the case of gunite or fiberglass in-ground pools, when there is a large amount of ground water, they could actually “Float” upwards like a boat if they didn’t have the weight of water in the pool to hold their place. This could mess up the plumbing, pool decking, electrical connections and possible wall cracking issues as well.

      Hope this helps!

  5. Jean Blair

    My liner got a tear on the bottom so I had to drain all the water out. Planning on getting a new liner in the spring. Can I leave my pool empty through the winter? It’s a 24 round.

    1. Trey Collier Post Author

      I’m sorry to hear that Jean. I wouldn’t recommend that you leave an above ground pool empty. The walls and upright supports are designed to support against the forces of the weight of the water from the inside pushing out. They are NOT designed to resist against the wind forces from the outside towards the middle of the pool. (the water normally does this) If you leave it empty, you will most likely be in need of a new pool too.

  6. Vaughn Berger

    Great article and one I’d like to repost on my blog with your permission. Vaughn Berger (Red Square Pools- Las Vegas, NV)

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