When should I close my pool in Virginia?

Close it when swimming ends and before the first hard freeze

The answer is your weather, not a calendar date. Close once the pool is done for the season and before freezing temperatures arrive. In practice that is earlier in colder parts of the state and later near the coast.

The freeze is the real deadline. Water that freezes in equipment cracks it: drain water from equipment such as filters, pumps, heaters, and piping, as freezing water can cause cracks, which can later cause leaks.^[1] Hayward's pump manual says to drain all water from pump and piping when expecting freezing temperatures or when storing pump for a long time,^[2] and adds that allowing the pump to freeze will void the warranty.^[2]

Closing a few weeks before that freeze is better than closing the night before. You get calm weather for the work, the water has time to take the chemicals, and the pool company, if you hire one, still has openings.

Not too early, either

Closing too early has its own cost. A covered pool with a spent chlorine residual can bloom during a warm October, and that bloom is what you meet in spring; see why a pool is green after opening. If the leaves are still falling and you are still swimming, wait, then close in one session.

The Portsmouth Health Department's operator guide gives a useful frame: the end of the operating season is the best time to inventory your equipment, prioritize and complete repairs, and prepare your facility for winter weather.^[4] That is a good time to look over the ladder, rails, skimmer lids and deck for damage and put repairs on next year's list.

What closing involves

The core of it is what the EPA's WaterSense pool guide describes. Winterize your pool by cleaning the pool water and all parts of the pool, balancing out pool chemicals, and adding winterization chemicals such as shock and algaecide, which kills bacteria and algae.^[1] Balancing matters because a chemical imbalance could corrode the pool and lead to structural damage.^[1] How to balance is in how to balance pool chemicals.

Then the equipment. Turn the power to the pump off before touching it, and drain the pump, filter and lines; leave the heater to a pro. If you need antifreeze in your system, use ONLY propylene glycol,^[2] and do not push water out of the lines with a compressor: purging the system with compressed air can cause components to explode, with risk of severe injury or death.^[2] A low-pressure blower is the manufacturer's alternative, and most people leave that part to a pool company.

Last is the cover. A winter cover is used over an extended period during the pool offseason to protect it from damage and debris.^[1] If you use a mesh safety cover, read its manual. One maker states the water level in the pool must be between 15" and 18" below the cover at all times, or the warranty will be voided.^[3] Through the winter, as debris collects on top of pool safety cover, cover must be swept to ensure that rain water can drain into the pool,^[3] since failure to keep top of cover clear may cause water to puddle and failure of pool cover.^[3]

Small things finish the job. Portsmouth's closing checklist says to dump out all test kit reagents or store in a refrigerator.^[4] The same applies when it is time to open: how to open a pool in spring picks up where this leaves off.

Cost and who does it

Closing is a manageable first job on a simple pool with no heater or salt cell. For pricing, see what opening and closing a pool costs in Virginia, and for the trade-off, open and close it yourself or hire a pool company.

Stop and call a pro if

• The plumbing needs blowing out or antifreeze. Compressed air can make components explode, so leave line purging to someone with the right equipment.^[2]
• The pump, heater or salt system is part of the shutdown. Gas heaters and electrical gear are not DIY jobs.
• You find a leak or cracked equipment. Water loss over the season is a repair question; a pool company can pressure-test the lines.
• The cover will not fit safely or sags on the water. A badly fitted safety cover is a hazard, and the maker says non-secured or improperly secured covers are a hazard.

Getting help in Virginia

If you hire a pool company, ask early, since closings cluster in the same few weeks. Browse pool and spa pros and more pool and spa answers. When you are ready, describe the job and local pros quote it.