How to Close Your Swimming Pool for Winter

Winterizing your pool involves balancing water chemistry, cleaning thoroughly, lowering water levels, adding winterizing chemicals, and covering the pool to protect it from freezing damage and debris.

1. Balance Water First. Start this process 3-7 days before closing. Test your water and adjust pH to 7.2-7.6, alkalinity to 80-120 ppm, and calcium hardness to 180-220 ppm. Shock the pool with chlorine to reach 1-3 ppm free chlorine. Proper chemistry prevents staining, scaling, and algae growth during winter months.
2. Remove All Debris. Vacuum the entire pool floor and brush all walls and steps. Remove all debris from skimmer baskets and pump basket. Clean the pool filter according to manufacturer instructions. Empty all pool accessories like ladders, toys, and floating devices. A clean pool prevents organic matter from decomposing and creating problems over winter.
3. Drain to Safe Level. Drain water to 4-6 inches below the skimmer opening for mesh covers, or 12-18 inches below for solid covers. Use your pool pump or a submersible pump to remove water. Never completely drain an inground pool as ground pressure can cause the shell to crack or pop out of the ground.
4. Prevent Frozen Pipes. Use a shop vacuum or air compressor to blow water out of all plumbing lines including skimmer lines, return lines, and main drain lines. Start with the skimmer line, then move to return jets, and finish with the main drain. This prevents pipes from freezing and cracking. Cap all return fittings and plug the skimmer.
5. Protect With Chemicals. Add winter algaecide according to package directions, typically 1 quart per 20,000 gallons. Pour in pool antifreeze to lines that cannot be completely drained. Add a winterizing chemical kit if desired, which typically includes algaecide, metal sequestrant, and enzyme products. Distribute chemicals by running the pump for 30 minutes.
6. Secure All Equipment. Drain the pool pump, heater, filter, and chlorinator completely. Remove drain plugs and store them in the pump basket so you don't lose them. Clean equipment thoroughly and store in a dry location. For above-ground pools, disconnect and drain all hoses and store them indoors.
7. Seal With Cover. Clean the pool cover before installation and inspect for damage. For safety covers, attach all springs and anchors properly. For solid covers, ensure proper water bags or cover clips are secure around the perimeter. The cover should be tight but not stretched. Add a cover pump if using a solid cover to remove standing water.