Closing Your Pool for Winter
Once the nights turn cold and you have stopped swimming, it is time to close the pool. A proper closing does two things: it protects your plumbing and surfaces from freeze damage over the winter, and it gives you far less to clean up when you reopen in spring. This guide walks through balancing the water, clearing the lines so nothing freezes, and getting a good cover on.
The Closing Sequence at a Glance
- Balance & clean Set chemistry to normal ranges, shock, add winter algaecide, then brush and vacuum.
- Clear the lines Drain below the skimmer, blow out and cap the plumbing, pull equipment drain plugs.
- Cover it Patch tears, fit the right cover, and secure it against wind.
- Monitor Pump off rain and snow and sweep debris off the cover every few weeks.
Why a Proper Closing Matters
A pool closed carelessly tends to come back wrong. Water left in the lines can freeze and crack the plumbing, unbalanced water can stain or scale the surface over the months it sits, and a pool shut down dirty often opens green. Spend an afternoon doing it right and you skip an expensive repair and a swampy spring cleanup.
Balance and Clean First
Before anything gets covered, leave the water clean and balanced. It has to sit like this for months, so do not cut corners here.
Balance the Chemistry
Set pH, total alkalinity, and calcium hardness to their normal swimming-season ranges, just as you would in summer. Water that drifts out of balance over winter eats at plaster and surfaces or leaves scale you will be scrubbing off in spring.
Shock and Algaecide
Give the pool a final shock and a dose of winter algaecide so nothing blooms while it sits. Add them with the pump running so they circulate fully, and let the chlorine drop back down before you close everything up.
Scrub It Down
Brush the walls, vacuum the floor, and skim the surface. Debris left behind stains the finish and feeds bacteria while the water sits still for months.
Lower the Water and Clear the Lines
Water expands as it freezes, and there is nowhere for it to go inside a sealed pipe or skimmer. That is what cracks plumbing over the winter, so the goal of this step is simple: get the water out of anything that can freeze.
Drain It Down
For in-ground pools, lower the water below the skimmer mouth or tile line. For above-ground pools, drop it just enough that the level sits below the skimmer and pump so neither cracks.
Blow Out the Lines
Push the water out of the plumbing with an air compressor or shop vac. When you see air bubbles instead of water coming from a line, cap or plug it right away. That seals the line empty so nothing is left inside to freeze.
Why it matters: Water left in skimmers, pumps, or plumbing can freeze, expand, and crack the line - one of the most expensive and most preventable winter repairs. Add pool-grade antifreeze to lines you can’t fully clear.
Protect the Equipment
Pull the drain plugs from the pump, filter, and heater so they drain fully and do not crack. Drop the plugs in the pump basket or a labeled bag so you can find them in spring. If you can, bring the pump and any other removable gear indoors for the winter.
Covering Your Pool
The cover keeps debris, sunlight, and water out all winter. What you use depends on your budget and what falls into the pool.
Choose the Right Cover
Your cover options run from a basic winter tarp up to a heavy-duty safety cover. Safety covers anchor to the deck and hold weight like snow or a stray animal, but they cost more. Standard winter covers are cheaper and rely on water tubes or weights around the edge to stay put.
Check for Tears
One small hole lets leaves, water, and debris straight into the pool you just cleaned. Patch any rips or worn spots before the cover goes on.
Secure It Well
For a standard cover, line the edges with water tubes or weights so wind cannot lift it. Safety covers anchor with straps mounted into the deck around the pool.
Winter Monitoring
A closed pool still needs the occasional look. A quick check now and then catches small problems before they turn into spring repairs.
Remove Excess Water or Snow
Pump off rain and melted snow with a cover pump. The weight of standing water sags the cover and can tear it.
Keep Debris Off
Leaves and branches add weight and wear the cover out faster. A quick sweep every few weeks is all it takes.
Closing is the less fun half of pool ownership, but the work pays off in spring. Balanced water, cleared lines, and a solid cover mean no cracked plumbing and no green water waiting for you. Do it right in the fall and reopening is mostly just taking the cover off.