Closing Your Pool for Winter in South Jersey: Water Level, Timing and What Not to Do

Published November 2, 2026 · A Clear Alternative Water, Pennsauken NJ, since 1991

Close your South Jersey pool when the water stays below about 65 degrees for several days in a row, which in most years means mid-October to early November. Balance and sanitize the water, lower the level only as far as your cover requires, blow out and plug the lines, and drain the pump, filter and heater. Most important: never drain an in-ground pool completely for winter. Groundwater pressure can lift or crack an empty shell or tear a liner. Keeping the right amount of water in all winter also makes spring opening easier and keeps refill needs small. A Clear Alternative delivers pool water across eight South Jersey counties; call 856-856-5210 any time.

When to Close a Pool in South Jersey

Most pool care guides, including Leslie's pool closing guide, say pool water should be consistently below 65 degrees before you close. Above that, algae can still grow under the cover. In South Jersey, warm spells often run into October, so watch water temperature rather than the calendar, and close before regular overnight freezes arrive.

Shore-area pools in Atlantic, Cape May and Monmouth counties tend to cool a little later than inland pools in Burlington, Camden, Gloucester, Salem and Mercer counties. Check the water temperature in the afternoon for a week before you decide.

Pool Closing Checklist

About a Week Before

• Clean the pool thoroughly: skim, brush and vacuum. Leaves left in the pool will stain the finish and feed algae all winter.
• Test and balance the water. Pool professionals generally aim for pH around 7.2 to 7.6 and total alkalinity in the normal range before closing.
• Check calcium hardness and stabilizer. If they are very high, this is the time to plan a partial drain and refill in spring rather than now.

Closing Day

1. Shock and add winter chemicals according to your closing kit's instructions, and let the pump run long enough to circulate them.
2. Clean or backwash the filter.
3. Remove accessories: ladders, rails, skimmer baskets, return fittings, cleaners and solar blankets.
4. Lower the water only as much as needed (see the next section).
5. Blow out the lines and plug them. Use a blower or shop vac to push water out of the skimmer and return lines, then plug the returns and install a skimmer plug or freeze-protection device while air is still flowing.
6. Winterize equipment. Remove the drain plugs from the pump, filter, heater and chlorinator so no water is left to freeze and crack them.
7. Install the cover tightly, following the maker's instructions for water bags, straps or safety cover anchors.

How Low Should the Water Be?

This is where many pool owners go wrong, and it is the step that decides how much water you need in spring. The right level depends on the cover and the pool type:

• Solid winter cover: In The Swim recommends about 4 inches below the skimmer. Solid covers rest on the water, so keeping the level up helps support the cover.
• Mesh safety cover: lower the water further, about 6 to 12 inches below the skimmer, because rain and melting snow pass through mesh and raise the level over winter.
• Skimmer cover plate or freeze plug: some setups allow the water to stay at its normal level. Follow your equipment's instructions.
• Fiberglass pools: many fiberglass pool makers advise keeping the water at or near normal level. Check your manufacturer's guidance before lowering.
• Above-ground pools: lower the water below the skimmer and return, or keep it at normal level if you use a skimmer cover plate. Never drain an above-ground pool fully; the liner can shrink and the walls can be damaged.

Always follow your cover's instructions first. Lowering too far leaves a solid cover unsupported and puts strain on the liner and the cover itself.

Why You Should Never Drain a Pool for Winter

An in-ground pool is designed to be full. The water inside pushes back against groundwater pressure from below. ProTuff's winterizing guide warns that an empty concrete, vinyl or fiberglass pool is exposed to groundwater pressure that can pop the shell out of the ground, tear a liner or crack plaster. Much of South Jersey has sandy soil and a high water table, especially near the shore and in low-lying areas, so this risk is real here.

A vinyl liner left without water over winter can also shrink, wrinkle or pull out of its track, which often means a new liner in spring. Keep the water in, and let the cover and winter chemicals do their job.

Common Pool Closing Mistakes

• Closing too early. Closing while the water is still warm invites algae under the cover and a green pool in spring.
• Leaving debris in the pool. Leaves left on the floor stain plaster and vinyl and use up winter chemicals.
• Skipping the line blowout. Water left in pipes can freeze and crack them, which means digging up the deck in spring.
• Forgetting the equipment drain plugs. A frozen pump or filter housing can crack in one cold night.
• Dropping the water too low. Going far below the skimmer on a solid cover pool leaves the cover unsupported and adds strain to the liner.
• Using a loose or torn cover. Gaps let in leaves and sunlight, both of which make spring cleanup harder.

If you are not comfortable with the blowout and plugging steps, a local pool service can close the pool for you. The water level advice above still applies.

Over the Winter

• Pump rain and snowmelt off a solid cover so it does not sag or tear.
• Clear leaves and branches off the cover regularly.
• Check the water level about once a month. If it drops a lot on a solid cover pool, look for a leak.
• Keep safety cover springs and anchors tight.

Planning Spring Water Now

Closing day is a good time to think about spring. Most pools lose some water over the winter to evaporation, splash-out from cover pumping, and the level you lowered for closing. Some need much more:

• A green or swampy pool at opening. Sometimes draining and refilling is faster than weeks of chemicals. Our guide to draining and refilling a green pool explains when that makes sense.
• A liner replacement. If your liner is faded, brittle or leaking, many owners schedule the replacement for spring, and the new liner needs to be filled quickly. See our guide on refilling after a liner replacement.
• High stabilizer or calcium. A partial drain and refill in spring brings those numbers down.

Knowing your pool's volume helps you plan. Our guide to how many gallons your pool holds walks through the math, and our pool fill service page explains how a delivery works.

Serving Eight South Jersey Counties

We deliver pool water to homeowners, swim clubs and pool builders in Burlington, Camden, Gloucester, Atlantic, Salem, Cape May, Mercer and Monmouth counties. See our service areas for the towns we cover.

When to Call A Clear Alternative

Call us in spring when you open a pool that lost water over winter, when you need a fast refill after a drain or liner change, or to book an opening-week delivery before the rush. Our tankers carry 6,200 gallons, so a top-off or full refill can often be done in a single visit or a few. A Clear Alternative is a family-run company that has served South Jersey since 1991 from 9230 Collins Ave in Pennsauken. Call 856-856-5210 any time, reach our office at 856-663-8088, or request a quote online.

Frequently Asked Questions

When should I close my pool in South Jersey?

When the water stays below about 65 degrees for several days in a row, which in most years is mid-October to early November. Close before regular overnight freezes.

Should I drain my pool for winter?

No. Never drain an in-ground pool completely. Groundwater pressure can lift or crack an empty shell or tear a liner. Lower the water only as far as your cover requires.

How far below the skimmer should the water be for a mesh cover?

Usually about 6 to 12 inches below the skimmer for a mesh safety cover, because rain and snowmelt pass through and raise the level. Follow your cover maker's instructions.

How low should the water be for a solid cover?

About 4 inches below the skimmer is common, because a solid cover rests on the water and needs support. Follow your cover maker's instructions.

Do I need to lower the water in an above-ground pool?

Lower it below the skimmer and return, or keep it at normal level if you use a skimmer cover plate. Never drain an above-ground pool fully.

Can you refill my pool when I open it in spring?

Yes. We deliver pool water in Burlington, Camden, Gloucester, Atlantic, Salem, Cape May, Mercer and Monmouth counties. Call 856-856-5210 to schedule.