Above-Ground Pool Winter Water Level: Exactly How Low to Drain It

Every fall, pool owners stare at the garden hose adapter on their above-ground pool and wonder: how much water am I actually supposed to pull out of this thing before I cover it up? Drain too much and you risk liner damage. Leave too much and ice will find its way into your skimmer. It is a frustratingly specific question with a frustratingly specific answer.

The correct water level to leave in an above-ground pool when closing it for winter is 4 to 6 inches below the mouth of the skimmer. That single number is the target that protects both your liner and your skimmer from winter damage. This article covers why that level is right, what goes wrong above and below it, how to drain to it accurately, and what to do with the lines and equipment once the water is where it needs to be.

Why the Skimmer Is Your Reference Point

The skimmer opening is the right reference point for one straightforward reason: it is the most freeze-vulnerable spot on your pool. When water sits at or above the skimmer throat, any ice sheet that forms on the surface can push directly into that housing and crack it. Skimmer bodies are plastic, and even a modest freeze-thaw cycle generates enough pressure to split them. Replacing a cracked above-ground skimmer runs $60 to $150 in parts plus labor, and it is entirely preventable. According to Zagers Pool and Spa, dropping the water below the skimmer is one of the non-negotiable steps in a proper above-ground pool closing.

The 4-to-6-inch range gives you a practical buffer. Four inches is enough to keep ice expansion away from the skimmer. Six inches is a reasonable upper limit because going much lower starts to reduce the water weight holding your liner flat against the pool wall, which creates its own set of problems explained in the next section.

What Happens If You Drain Too Much

A vinyl liner needs water weight to stay seated. When you remove too much water, the liner loses tension and can shift, wrinkle, or pull away from the coping rail. In cold weather that movement becomes permanent: the vinyl stiffens and the creases set in. When you refill in spring, those wrinkles do not just disappear. At minimum they are cosmetically annoying; at worst they become stress points that eventually crack or tear, leading to an early liner replacement. Above-ground pool liners cost $200 to $600 installed depending on size and thickness, so protecting the one you have is worth a few minutes of attention now.

Some pool owners drain almost completely because they think it is safer or because they have heard of people storing inflatable pools that way. Above-ground steel or resin-frame pools with vinyl liners are a completely different situation. The liner is not meant to sit dry through a winter, and the frame can actually shift or rack inward without the water weight counteracting the coping tension.

What Happens If You Leave Too Much Water In

Leaving the water too high is the more common mistake, mostly because draining feels like extra work. If the water level is at or above the skimmer opening when you close the pool, ice will form inside the skimmer body. That ice has nowhere to go except outward, and plastic skimmer housings crack under that pressure. If your return fittings are also underwater when the surface freezes, those can crack too.

Beyond the skimmer, too-high water can make your winter cover work against you. Most above-ground pool covers are designed to sit slightly below the water line with a cable and winch system, but if the pool is too full, the cover may not seat properly around the perimeter, letting debris funnel in around the edge all winter. The Swimming Pool Store notes that improper water levels and cover fit are two of the main reasons pool owners open to green, murky water in spring.

How to Drain to the Right Level

Draining an above-ground pool to a precise level is easier than it sounds. Here is the process:

1. Identify your target. Find the center of the skimmer opening. Your finished water level should sit 4 to 6 inches below that point. Use a tape measure and mark the pool wall with a piece of painter’s tape so you have a visible target while draining.
2. Use a submersible pump or siphon. A small submersible utility pump (available for $40 to $80) makes this fast and controllable. Run it out through the backyard to a drainage area at least 10 feet from the pool. Avoid draining directly onto hardscaping where pooling can occur.
3. Check your municipality’s rules. Some areas require pool water to be dechlorinated before draining to a lawn or storm drain. A brief run of your circulation system without adding chlorine, or a dose of sodium thiosulfate, brings the level down before you drain. The Canadian winters closing guide from Mario’s Pool and Spa covers this point well for readers in regions with strict discharge rules.
4. Stop at your mark. Watch the tape marker and shut off the pump when the surface hits 4 to 6 inches below the skimmer. Do not walk away and let it run unattended or you risk over-draining.
5. Drain and plug the lines. Once the water level is set, blow out the return and skimmer lines using a shop vac on exhaust mode or a small air compressor. Plug the return fitting with an expansion plug and plug the skimmer line from inside the skimmer. Any water remaining in above-ground plumbing lines that are exposed to outdoor temperatures will freeze and crack fittings or the pump housing.

Say your pool is a 24-foot round with a 52-inch wall. At full capacity that holds about 13,500 gallons. Draining 4 to 6 inches below the skimmer removes roughly 1,000 to 1,500 gallons depending on your exact skimmer height, leaving you with around 12,000 gallons sitting safely in the pool all winter. That is enough water weight to hold the liner flat through multiple freeze-thaw cycles.

What to Do With Your Equipment Before You Cover

Once the water is at the right level and the lines are blown out, take care of the equipment. Remove the pump and filter entirely if possible – store them in a garage or basement where temperatures stay above freezing. Submersible pump impellers and filter tanks can crack if water freezes inside them. Royal Swimming Pools recommends removing and storing above-ground equipment as a standard part of the closing process, rather than leaving it connected and hoping the cold does not reach it.

If you have a heater in the plumbing loop, that needs special attention too. Residual water in a heater heat exchanger will freeze and destroy it. Blow the heater lines out just like the return and skimmer lines, and confirm the drain plugs are out. Keeping your pool water balanced through winter also protects the liner and any metal components from corrosion even while the pool is covered and sitting idle.

The Cover Question: Matching It to Your Water Level

Your winter cover is doing two jobs: keeping debris out and protecting the surface from UV and weather. Most above-ground pool winter covers use a cable-and-winch system that cinches around the outside of the wall. They are designed for water levels that sit a few inches below the pool rim, which is roughly where you end up after draining 4 to 6 inches below the skimmer on most pools.

Add a cover pump or water bags to keep the cover from sagging and collecting rainwater. A cover loaded with standing water puts stress on the cable system and can push the cover partially into the pool if enough weight accumulates. AquaDoc makes a winter cover treatment that you dose before closing to keep algae from taking hold under the cover all season, which pairs well with getting the water chemistry right before you shut everything down.

For a full closing checklist that covers chemical timing and cover placement together, the JoCo Pools closing FAQ is a practical resource worth bookmarking.

Common Mistakes to Avoid

• Draining to the bottom return fitting: Some owners think “below the return” means they are safe, but if the return fitting is lower than the skimmer, they may have already over-drained the pool. Always use the skimmer as your reference, not the return.
• Skipping the blow-out on the lines: Even a small amount of water left in an above-ground return line that sits outside can freeze and crack the fitting where it enters the wall. A $15 expansion plug and five minutes with a shop vac prevents a $100 repair.
• Closing with unbalanced water: Water that goes into winter with a pH above 7.8 or below 7.2 will do months of slow damage to the liner, fittings, and any remaining metal hardware. Balance your chemicals before you drop the level and cover.
• Assuming the cover will do all the work: A winter cover keeps debris out, but it does not replace proper chemical treatment or protect against ice damage from high water. Both steps are required.

Frequently Asked Questions

How much water should I leave in an above-ground pool for winter?

Leave the water level 4 to 6 inches below the skimmer opening. This protects the skimmer from ice damage while keeping enough water in the pool to hold the liner flat and prevent shifting or creasing during cold weather.

Can I completely drain an above-ground pool for winter?

No. Completely draining an above-ground vinyl liner pool allows the liner to lose tension, shrink, and develop permanent creases. Cold temperatures stiffen vinyl quickly, and wrinkles that set in winter often do not relax when the pool refills in spring. Always leave the recommended amount of water in the pool.

What happens if I leave too much water in my above-ground pool over winter?

If the water sits at or above the skimmer opening, ice forming on the surface will push into the skimmer housing and can crack it. Keep the level at least 4 inches below the skimmer mouth. Also check that your return fittings are above the water line so they are not submerged when the surface freezes.

How much water do I drain from a 24-foot round above-ground pool for winter?

A 24-foot round pool at 52 inches deep holds roughly 13,500 gallons. Draining to 4 to 6 inches below the skimmer removes approximately 1,000 to 1,500 gallons, leaving around 12,000 gallons in the pool. The exact amount depends on your skimmer height, but this range is a reliable starting estimate.

Do I need to drain the plumbing lines in an above-ground pool before winter?

Yes. After lowering the water level, blow out the return and skimmer lines and plug them with expansion plugs. Above-ground plumbing lines are exposed to outdoor air temperatures and any water left inside will freeze, expand, and can split fittings or crack the pump housing. This step takes less than 15 minutes and prevents expensive repairs.

The short version: drain to 4 to 6 inches below the skimmer, blow out your lines, remove or protect your equipment, and balance your water before you cover. Get that water level right and your liner and skimmer will both be waiting for you in good shape come spring.