How to Close Your Pool for Winter in Massachusetts and Connecticut

Closing your pool correctly is one of the most important things you can do to protect your investment. In New England, where temperatures regularly drop well below freezing, a poorly winterized pool can mean cracked pipes, damaged equipment, and a green swamp waiting for you in spring.

Done right, a proper fall closing means a faster, easier opening next season — and no expensive surprises.

Most homeowners in Western Massachusetts and Northern Connecticut close their pools between mid-September and mid-October, once water temperatures consistently drop below 60°F.

Closing too early — while water is still warm — can actually cause more algae problems over winter. Cooler water is less hospitable to algae growth, and the closing chemicals work better and last longer when the water is cold.

Don't wait until a hard freeze is imminent. Rushing a closing under pressure leads to missed steps.

Properly balanced water going into winter protects your pool surfaces and makes spring startup easier. Test and adjust:

• pH: 7.2 – 7.4
• Total Alkalinity: 80 – 120 ppm
• Calcium Hardness: 175 – 225 ppm
• Free Chlorine: 1 – 3 ppm

Balance chemistry at least 1–2 days before closing so the chemicals have time to circulate and stabilize.

Shock the pool 3–5 days before closing to eliminate bacteria, algae spores, and organic waste that would otherwise sit in the water all winter.

Use a full dose of calcium hypochlorite shock (1 lb per 10,000 gallons minimum). Allow chlorine to return to normal levels (1–3 ppm) before adding winterizing chemicals — high chlorine will degrade them.

Once chlorine is back in range, add your winterizing chemical kit:

• Winter algaecide — a slow-release formula designed to last through the off-season
• Stain and scale preventer — protects surfaces from mineral deposits and staining
• Enzyme treatment (optional but recommended) — breaks down oils and organics that accumulate over winter

Add chemicals with the pump running and allow them to circulate for several hours.

Before shutting down, clean everything:

• Skim the surface and remove all debris
• Brush walls and floor
• Vacuum the pool completely
• Clean the skimmer baskets and pump basket
• Backwash or clean the filter

A clean pool going into winter means far less work in spring.

For pools with a mesh safety cover or solid cover with a pump, lower the water level:

• Mesh covers: Lower water 12–18 inches below the skimmer opening
• Solid covers: Lower water 3–6 inches below the skimmer

Do not drain the pool completely — water provides structural support for the pool shell and helps prevent the liner from shrinking or shifting.

This is the most critical step for freeze protection. Water left in underground pipes will freeze, expand, and crack the plumbing.

Using a shop vac or air compressor:

1. Blow out each return line from the equipment pad until no water remains
2. Immediately plug the return fitting with a winter plug (expansion plug)
3. Blow out the skimmer line and plug the skimmer throat
4. Blow out any other lines (cleaner lines, spa jets, water features)

If you're not confident doing this yourself, have a professional handle it — a cracked underground pipe is one of the most expensive pool repairs there is.

Pump:

• Remove drain plugs from the pump housing and volute
• Store drain plugs in the pump basket so you don't lose them
• Remove and store the pump lid O-ring with a light coat of lubricant

Filter:

• Sand filter: Set to "winterize" position (if available) or remove the drain plug
• Cartridge filter: Remove and clean the cartridge; store indoors if possible
• DE filter: Backwash, then remove the drain plug and open the air bleeder

Heater:

• Remove drain plugs from the heater header
• Turn off the gas supply

Chlorinator/Salt Cell:

• Remove and clean the salt cell; store indoors
• Remove the inline chlorinator and store with the lid off

All equipment:

• Disconnect any electrical connections that could be damaged by moisture
• Cover the equipment pad with a tarp if it's exposed to the elements

The skimmer is the most vulnerable part of the pool to freeze damage. Options:

• Skimmer cover/plug: Install a Gizzmo or similar expansion plug in the skimmer throat to absorb ice expansion
• Skimmer cover plate: Install a cover plate over the skimmer opening to keep debris out

Never leave a skimmer open and full of water going into winter.

A quality cover is your pool's best protection over winter.

Safety covers (mesh or solid, anchored to the deck) are the best option — they keep debris out, prevent accidental falls, and last for years. See our safety cover page for more information.

Standard winter covers (water bag covers) are less expensive but require water bags or weights around the perimeter and need to be monitored for sagging and debris accumulation.

Make sure the cover is tight and secure. A loose cover can blow off in a storm and leave your pool exposed.

Before you're done:

• All lines blown out and plugged
• All equipment drain plugs removed
• Skimmer protected
• Cover installed and secured
• Pump and filter power turned off at the breaker
• Gas supply to heater turned off

Closing a pool properly takes time, the right equipment, and attention to detail. Our fall closing service covers everything — water balancing, blowing out lines, winterizing equipment, and cover installation.

Contact us to schedule your fall closing in Western Massachusetts or Northern Connecticut.