Updated · Make This Useful
Pool closing checklist
Close a pool in the order the water leaves the system: balance and shock, clean it, add the winter chemicals while the pump still runs, lower the level to suit the cover, blow out and plug every line, drain the pump, filter and heater, then fit the cover. The rule that matters most is to leave no water where it can freeze. Ice splits pump housings, filter tanks and skimmer throats, and the owner finds the crack at opening.
Edit the closing list
From the walk-around to the owner’s winter note. Strike the lines for equipment this pool does not have, such as a heater or a main drain, and write the cover type at the top.
Pool closing checklist
- Walk the pool: cover type, equipment, heater, leaks, anything changed
- Photograph the liner or plaster, deck, cover and equipment pad
- Test the water; balance pH, alkalinity and calcium hardness
- Shock per the label, early enough for chlorine to fall before algaecide
- Skim, brush walls and floor, vacuum; empty skimmer and pump baskets
- Ladders, rails, return fittings and skimmer baskets out, dried, stored
- Winter algaecide and stain treatment per the label, pump still running
- Clean the filter: backwash sand or DE, hose off or soak cartridges
- Lower the water to the level this cover needs; never drain the pool
- Breaker off; timer and automation off; heater gas valve closed
- Blow out returns, skimmer and cleaner lines from the equipment pad
- Plug returns as they bubble; shut the main drain valve to hold air
- Skimmer: pool antifreeze if winters freeze hard, then plug or guard in
- Drain pump, filter, heater and chlorinator; plugs go in the pump basket
- Above-ground: pump and filter unhooked, drained and stored dry
- Cover on and tight: springs tensioned, or water bags snug at the edge
- Tag the pad: what is plugged, drained, open and stored, and where
- After photos: cover, water level, plugs in place, equipment pad
- Tell the owner what to watch: cover water, straps, the level below
How low should the pool water be for winter?
Below the skimmer mouth on most inground pools, so ice cannot form in the skimmer throat. The cover decides how far. A solid cover held down with water bags floats on the water and needs it close underneath to carry rain and snow. A mesh safety cover lets rain and snowmelt through, so start lower and leave room for the level to climb. When the cover maker gives a level, use theirs.
The expensive mistake is draining too far. An inground pool emptied for winter can lift out of the ground when the water table rises, and a vinyl liner left dry shrinks, wrinkles and can tear when it is refilled. Above-ground pools stay mostly full too: drop them below the skimmer and the return, or seal both with a winter skimmer plate and a return plug.
Should you blow out the lines or use pool antifreeze?
Blow them out every time, and treat antifreeze as the backup. Air clears the returns, the skimmer line and any cleaner line; plug each return as the bubbles come through and close the main drain valve once it bubbles, so an air lock holds the water out. Where winters freeze hard, pour antifreeze made for pools into the skimmer line before its plug. Car antifreeze never goes in pool plumbing; it is toxic.
In places where freezes are short and rare, many pools are never closed at all. The owner keeps the water balanced and a freeze sensor turns the pump on through cold nights, because moving water holds off a brief freeze in the pipes. If you service those pools, test the freeze sensor each fall and write on the invoice that the pool was left running on purpose.
What should pool owners watch over the winter?
Water on the cover, the fastenings and the level underneath. Rainwater pooled on a solid cover is heavy, stretches the cover and is a drowning risk for children and pets, so the owner needs a cover pump and the habit of using it. Straps, springs and water bags get checked after every storm. If the level under a mesh cover climbs toward the skimmer, or drops fast, they should call you.
Frequently asked questions
When should you close a pool for the winter?
Once the water stays cool, and before the first hard freeze. Algae slows down in cold water, so a pool closed during a warm spell can go green under the cover before winter sets in. Leave it too late and you are blowing out lines while the plumbing is already freezing. If a warm week follows the closing, tell the owner which winter chemical to top up.
Can you close a pool that is green or cloudy?
Clear it first. Algae does not die under a cover; it waits, and the pool opens worse than it closed. Brush, shock and filter until the water is clear, cleaning the filter as the pressure climbs, which may take a second visit. Price that cleanup as its own line and tell the owner before you start, so the closing price they were quoted still means what it said.
Should the pool pump come out for winter?
On most above-ground pools, yes: unhook the pump and filter, drain them and store them somewhere dry. Inground equipment stays plumbed in, drained, with every plug out. Do not wrap a motor in plastic, which traps condensation against it; a breathable cover keeps the rain off. Drop the drain plugs in the pump basket, so whoever opens the pool finds them in spring.