What You’ll Need

Tools

 

Skimmer net

 

Pool vacuum

 

Protective eyewear

 

Chemical-resistant gloves

 

Backwash hose

 

Supplies

 

pH testing kit

 

Scale and stain remover

 

Winterizing pool chemicals

 

Algaecide

 

Antifreeze

 

You had a complete summer of enjoyment in the pool, but now it’s time to winterize your pool. Follow Leinteriore’s pool closing checklist to know exactly how to winterize your pool and protect it from freezing temperatures whether you have an inground pool or an above ground pool.

 

Your pool will be clean, clear, and ready for another season of fun when warmer days return.

 

Let’s dive in — here’s how to close a pool for winter properly.

Inground Pool Closing vs. Above Ground Pool Closing

Inground Pool Along Ground Pool

Add winterizing chemicals\tAdd winterizing chemicals

Install freeze plugs, Add a skimmer plug

Use a pipe blowout device

Secure the cover with cable and winch

Use a submersible pump, Use a submersible pump

Skimmer guard installation Water bags to secure the cover

Add a safety or winter cover Install a winter cover

Add 1 gallon of pool antifreeze per 10 ft of piping\tAdd a leaf net

 

Add a leaf net—

 

Step 1: Deep Clean the Pool

 

Leaving debris, leaves, or algae in the pool over the winter can stain and damage it by spring.

 

Here’s what to do before you cover it:

 

Add scale and stain remover one or two days before closing.

 

Skim leaves and floating debris with a skimmer net.

 

Scrub the walls and floor of the pool with a pool brush.

 

Use a vacuum to scrub the pool for small dirt particles.

 

Step 2: Balance the Water Chemistry

 

Before closing your pool, check the pH, alkalinity, and calcium hardness levels. Poorly balanced water can damage the liner or tiles.

 

Target these ranges before winter:

 

Alkalinity: 80–120 ppm

 

pH: 7.3–7.6

 

Calcium hardness: 175–225 ppm

Try to keep readings near the higher end — that helps your winterizing chemicals last longer.

 

Step 3: Shock the Pool Water

 

“Shocking” kills bacteria and algae before you seal the pool.

 

You can use either chlorine-based or non-chlorine shock treatments.

 

(Chlorine is stronger but avoid it for above-ground pools — it can damage vinyl liners.)

 

How to Shock the Pool:

 

Wear gloves and goggles.

 

Read the instructions on your product carefully.

 

Dissolve the shock in a ¾-full bucket of warm water, if needed.

 

Pour it all around the edges evenly.

Let the pump and filter run for 12 hours in order to circulate the water.

 

If the pool is extra dirty, then repeat the process.

 

Your final chlorine level should be between 1–3 ppm.

 

Step 4: Add Algaecide (Optional)

 

Shocking typically controls algae, but you can add an algaecide for extra protection.

 

Wait at least 24 hours after shocking, as a mixture of the two chemicals neutralizes their effectiveness.

 

Run the pump for an additional 24 hours to circulate the algaecide.

 

You can also check underneath the pool cover in midwinter; if algae is present, add another dose.

 

Step 5: Backwash the Filter

 

This will help in preventing algae growth inside your filter during winter.

 

Turn off the pool heater and filter.

 

Set the valve to the “backwash” or “drain to waste” position.

 

Attach the backwash hose, if necessary.

 

Turn the filter on until the water is clear, about 3–5 minutes.

 

Switch to “rinse” for 30 seconds, then turn off.

 

(Only for sand filters — skip if you have a cartridge or DE filter.)

 

Step 6: Lower the Water Level

 

Never completely drain the water from your pool-that can cause the liner to dry out or crack.

 

Lower the water level slightly, according to your pool type and the local temperatures.

 

Above Ground Pool:

 

If using a skimmer plate, no need to drain water.

 

If not, lower it just below the skimmer line but not too low — the water should still be well above the cover.

 

Inground Pool:

 

If freezing temperatures occur in your area, lower the water below the skimmer or tile line.

 

Follow your cover manufacturer’s guidelines:

 

Mesh cover: Lower 12–18 inches below skimmer.

 

Solid cover: Lower 3–6 inches below skimmer.

 

Step 7: Clean and Store Equipment

 

Water left in the system can create freezing damage.

 

Follow the proper steps based on your filter type:

 

Cartridge filter: Open the pressure valve, remove the cartridge, and rinse clean; then let it dry.

 

DE Filter: If equipped, open the housing, pull out grids, gently rinse, and allow to air dry.

 

Sand filter: Already cleaned by backwashing. No extra step needed.

 

Store pumps, filters and small parts, such as gauges and plugs, indoors or under a tarp to protect them from frost.

 

Step 8: Blow Out Pool Lines

 

Taking water out of the lines would prevent bursting and frozen pipes.

 

Remove skimmer baskets and return fittings.

 

An air compressor attached to the pump drain plug

 

Turn it on. When you see water blowing from the skimmer or jets, stop

 

Dry out the skimmer and plug it.

 

Watch for air bubbles in the return lines – when they appear plug them too.

 

Add about 1 gallon of pool antifreeze per 10 feet of pipe for added security.

 

Step 9: Add a Winterizing Pill

 

Winterizing pills float on the water and slowly release enzymes that prevent stains and bacteria buildup.

 

They come in different sizes depending on the capacity of your pool.

 

To Use:

 

Shake the pill in its wrapper.

 

Open it with the piercing tool.

 

Drop it into the pool and let it dissolve slowly all winter.

 

Step 10: Add an Air Pillow (Above Ground Pools)

 

An air pillow absorbs the pressure from expanding ice to help protect your pool walls.

 

Steps:

 

Fill the pillow to 60–80% full.

 

Tie it with a rope at the pool’s edge to center it.

 

Place it under the pool cover.

 

Step 11: Cover the Pool

 

Unlike your AC, your pool must be covered for winter.

 

Choose between mesh or solid vinyl covers:

 

However, mesh covers are less costly to buy and also easier to keep clean, but they allow small debris through.

 

Solid covers block everything but may need a small pump to remove rainwater or melted snow.

 

Always keep children and pets away — even water pooled on top of the cover can be dangerous.

 

Step 12: Monthly Winter Monitoring

 

Check your pool monthly during the cold season:

 

Test levels of chemicals: alkalinity 80-120 ppm, pH 7.3-7.6, calcium 175-225 ppm

 

Remove excess snow or water from the cover.

 

Add algaecide at midwinter if necessary. Wipe off debris that collects on equipment. Store all accessories in a cool, dry place, away from sunlight. When to Close Your Pool Timing depends on your region, but a general rule: Close your pool when temperatures are consistently below 65°F. If you close too early while it’s still warm, algae can bloom. If you wait until 32°F or below, freezing water will damage your pool system. DIY or Hire a Pro While saving money by closing your pool yourself is great, balancing the chemicals correctly can be challenging. If you’re not sure, or prefer a trouble-free service, hire a local pool closing expert via Leinteriore. Professional cost: Approximately $157.50–$315 (compared to $150–$300) DIY cost: Approximately $52.50–$157.50 (up from $50–$150). While DIY is cheaper, professionals make sure your pool lines, filters, and walls are inspected to help you avoid costly repairs later.