How to Close Your Above Ground Pool for Winter — a simple, step-by-step guide

Closing (winterizing) your above ground pool the right way protects the liner, pump, filter, and hardware — and makes opening in spring much easier. Below is a clear, easy above ground pool winterizing checklist with timing, supplies, a step-by-step process, and pro tips on how to close your above ground pool for winter. Use this guide to close your pool for winter like a pro and avoid common freeze-season headaches.

When to winterize

Start closing your pool when nightly temperatures consistently fall below about 65°F (18°C) — waiting until it’s cool reduces algae growth and makes chemicals work better. Timing varies by region; don’t close too early when warm spells return.

Supplies you’ll need (above ground pool winterizing checklist — supplies):

• Pool test kit (pH, total alkalinity, chlorine).

• Chlorine shock (pool shock).

• Algaecide and a winterizing chemical kit (if desired).

• Pool vacuum, skimmer net, and brush.

• Air pillow (for solid cover users) and winter cover (solid or mesh), cable & winch kit or cover weights.

• Shop vacuum or compressor (for blowing out lines) OR pool antifreeze (propylene glycol) for lines.

• Basic tools: screwdrivers, wrench, stainless hose clamps, storage bins for small parts.

• Storage space (dry, frost-free area) for pump, filter, skimmer baskets, ladders, and accessories.

Step-by-step winterizing guide for above ground pools:

1) Clean thoroughly — remove debris & scrub

Remove leaves, vacuum the floor, skim the surface, and brush the walls. Clean the filter (backwash or cartridge clean) so you’re closing with the cleanest water possible — this reduces winter algae and staining.

2) Balance water chemistry (very important)

Test and adjust pH, total alkalinity, and calcium hardness to manufacturer-recommended ranges before you shock. Balanced water helps chemicals work and prevents liner damage while the pool sits unused. Aim for stable levels according to your test-kit or product labels.

3) Shock the pool and add winter chemicals

Shock the pool with chlorine to remove contaminants, then add a winter algaecide and a winterizing chemical kit per label directions if you use one. This reduces the risk of algae and organic staining over winter.

4) Lower the water level (if instructed)

For many above ground pools, lower water to below the skimmer or as recommended by the pool cover instructions so the cover won’t be pushed off by ice or snow. Check your cover manufacturer’s instructions — some covers require different water heights.

5) Remove and store equipment & accessories

Disconnect hoses, remove the pump, filter (or drain and store cartridges), skimmer baskets, ladders, solar covers, and any floats or toys. Store small parts and chemicals in a dry, locked area. For sand filters, drain and store per manufacturer instructions. Failure to drain equipment can cause freeze damage.

6) Winterize plumbing & lines

Blow out or drain lines to remove water that could freeze and crack plumbing. Use a shop vacuum or air compressor to clear skimmers, returns, and pump lines; plug lines with winterizing plugs or add pool antifreeze (propylene glycol) into low points where required. Follow the filter and pump manufacturer’s winterizing guidance.

7) Install air pillow & cover the pool

If you use a solid cover, place an air pillow under the center of the cover to prevent ice from pushing into the walls. Pull the winter cover across and secure it with a cable & winch kit or cover weights; for above ground pools, wall bags or straps help keep the cover tight against wind. For some climates, a mesh cover may be preferred to let snow melt through — check local recommendations.

8) Final check & monthly inspection

Walk the perimeter and confirm the cover is secure. Mark the cover and return area for safe visibility. Check the cover, tension, and water level monthly during winter; remove snow/ice buildup carefully to protect the cover.

Tips specific to above ground pools:

• Don’t forget the walls/liner. Above ground vinyl liners can wrinkle if water level changes too much; follow the cover and liner manufacturer’s instructions.

• Store the pump and filter indoors if your equipment won’t be in a heated shed — even residual moisture can freeze and damage components.

• Use floating tennis balls or milk jugs (temporary hacks) to absorb oils and weigh down covers if you don’t have a pillow or weights — popular DIY hacks, but follow manufacturer guidance for best results.

Common mistakes to avoid:

• Closing too early (when water is still warm) — increases risk of algae growth during winter. Wait until temps are consistently cooler (≈65°F or below).

• Leaving water in lines, pump housing, or filter — freeze damage is expensive to repair. Always drain or blow out lines.

• Discharging chlorinated water into storm drains or landscaping — check local rules and dechlorinate if required. (Some areas regulate pool discharge.)

Quick winterizing checklist:

• Clean: skim, vacuum, brush

• Test & balance: pH, alkalinity, hardness

• Shock pool and add winter algaecide/winter kit

• Lower water to cover-recommended level

• Remove/store pump, filter parts, skimmer baskets, ladder

• Drain/blow out plumbing & add pool antifreeze if needed

• Install air pillow (if using solid cover) and secure winter cover (cable & winch or weights)

• Store chemicals safely and lock away

• Monthly winter check: cover tension, remove heavy snow/ice, inspect water color

FAQ — short answers

Q: Can I close my above ground pool myself?

A: Yes. Most owners can winterize their above ground pools safely with the right supplies and by following a step-by-step process. Many retailers and guides (Leslie’s, InTheSwim, Swim University) offer checklists and kits.

Q: Do I need a professional?

A: Hire a pro if you’re unsure about plumbing blowouts, have complex equipment, or prefer a guaranteed service — otherwise, DIY winterizing is common and cost-effective.

Q: What about saltwater or chlorine pools?

A: Both require balancing and the same mechanical winterization steps; follow any salt system manufacturer guidance when closing a salt chlorinated pool. Also consider specific winter chemicals for your system.

Closing your above ground pool properly takes a few hours, a little planning and a checklist. Do it right and you’ll save time, money and stress when spring arrives!