MaintainlyWhen should you close and winterize your pool?
Close and winterize the pool once a year. The commonly recommended range is yearly, before the first frost. Water left in the pipes, pump and filter freezes, expands and cracks them. It is seasonal work, best done in autumn / fall.
Closing the pool protects the plumbing and equipment from freezing. Water left in pipes, the pump or the filter expands as it freezes and cracks them. Where winters are mild, the pool can often stay running instead.
Why does closing your pool matter?
Water left in the pipes, pump and filter freezes, expands and cracks them.
What happens if you skip closing your pool?
Freeze damage to lines, pumps and filters is not found until spring, when the pool should be opening.
How do you do it?
- Balance and shock the water. Clean, balanced water under the cover avoids a swamp in spring.
- Lower the water level. How far depends on the cover: well below the skimmer for a mesh cover, less for a solid one, and some covers need no lowering. Check the cover maker’s manual.
- Blow out and plug the lines. On an in-ground pool, blow water out of the plumbing and fit expansion plugs at the pool so no water can sit in the pipes.
- Drain the equipment. Drain the pump, filter, heater and chlorinator through their drain plugs, and store the pump and filter indoors if you can.
- Fit the cover securely. Use a cover sized to the pool, fitted tightly, and keep a solid cover clear of standing water through winter.
What does it take?
How do you know closing your pool is overdue?
- The first frost in the forecast
- Water temperature staying below about 18°C (65°F)
What do people get wrong?
- Closing while the water is still warm, so the winter chemicals are used up early and algae grows under the cover
- Draining the pool completely instead of lowering it to the level the cover needs
- Leaving water in the pump or filter
When should you stop and call someone?
If you are not sure the lines are fully blown out, have a pool service close it.
Does this differ in the US, UK, Australia or Canada?
United States
Close before the first hard freeze in northern states. Pools in the Sun Belt often run all year.
United Kingdom
Close in autumn, before the first frosts.
Australia
Many pools run all year. In cooler regions, close in autumn.
Canada
Close in early autumn, before overnight freezes begin.
Frequently asked questions
Why does closing your pool matter?
Water left in the pipes, pump and filter freezes, expands and cracks them.
What happens if you skip closing your pool?
Freeze damage to lines, pumps and filters is not found until spring, when the pool should be opening.
Does closing your pool differ by country?
Cold and temperate climates. Southern hemisphere: April to May. Not needed where pools stay open all year.
When in the year is closing your pool best done?
This is seasonal work. Plan it for autumn / fall, before the weather it protects against arrives.
How we put this together
The figures, intervals and legal points on this page were checked against the sources listed below. The default interval and accepted range are the ones Maintainly uses in its task library. Costs and times are typical ranges and vary by region and by home. Your own manufacturer's instructions come first, and gas, electrical and structural work belongs with a qualified professional. How we research and write.
Sources
- The Right Time to Close Your Pool, Hayward. Checked 11 October 2026.
- Ten Essential Steps to Closing Your Pool, Hayward. Checked 11 October 2026.
Next steps
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