A good pool closing starts before the first freezing night. Give yourself time to test the water, collect the right supplies, and arrange professional help for equipment and underground plumbing. A calm, planned closing is easier than trying to find a missing plug as the temperature drops.
This guide is for seasonal shutdown in a climate where freezing is expected. Your pool builder, equipment manuals, chemical labels, and cover instructions determine the details for your system. Pools that operate throughout a mild winter need a different plan. Browse our Pool Winterizing collection as you build your own supply list.
1. Clean the pool and inspect your supplies
Skim leaves, brush the walls and floor, and vacuum settled debris. Empty baskets and inspect the cover for tears, damaged straps, or missing hardware. Removing debris now gives you a cleaner starting point for water treatment and makes it easier to notice existing stains or surface damage.
Set aside your test kit, winter plugs, equipment manuals, and labeled storage containers. Record the pool volume so chemical amounts come from the correct label calculation, rather than a guess based on pool shape.
2. Test and balance the water
Test sanitizer, pH, total alkalinity, and calcium hardness with supplies appropriate for your pool. Check stabilizer when relevant to your sanitizer system. Compare results with the ranges recommended for your surface, equipment, and treatment program. Our pool testing kits and tools can help you prepare for this step.
Make measured adjustments separately, allowing the circulation and waiting time stated on each label, then retest. Do not assume clear water is balanced water. Write down the final readings and the date; that record gives you a useful reference when you reopen.
3. Shock according to your treatment program
Complete the required shock treatment before adding winterizing chemicals, following the product directions and your pool professional’s closing plan. DryTec cal-hypo pool shock is one option for pools whose treatment program and equipment allow calcium hypochlorite. Confirm compatibility before choosing it.
Use the dose specified for your actual water volume and conditions. Wear the protective equipment required by the label, keep children and pets away, and never mix chlorine products with each other, acids, or other chemicals. Only predissolve a product if its label specifically directs you to do so.
4. Add compatible winter chemicals
A winter treatment may include an algaecide, a stain-control product, or another closing aid suited to your water. Choose the products your pool needs instead of adding every bottle in a kit automatically. Check compatibility, application order, sanitizer limits, and circulation requirements on every label.
Keep chemicals in their original containers and use clean, dedicated measuring tools. A closing chemical does not replace physical freeze protection for pipes or equipment. Finish all required circulation before shutting the system down for winter.
5. Set the correct winter water level
There is no single lowering measurement that fits every pool and cover. Follow your pool builder’s and cover manufacturer’s instructions, including the chosen method of protecting skimmers and returns. Some systems require lowering; others use different arrangements.
Do not empty the pool as a routine closing step. The remaining water can support the structure and cover. Monitor the level during draining, and never let a pump run dry. If groundwater, liner movement, or drainage restrictions are concerns, have a qualified pool professional handle this stage.
6. Winterize equipment and plumbing
Clean the filter according to its manual, then follow the shutdown, electrical isolation, pressure-release, and draining instructions for the pump, filter, heater, sanitizer, and connected accessories. Never open pressurized equipment. Remove the specified drain plugs and store small parts together with clear labels.
Underground lines need the correct method of clearing water, sealing returns, and protecting skimmers and other branches. Ask an experienced pool professional to handle unfamiliar plumbing, main drains, or air-pressure work. Excessive pressure can damage equipment and cause injury. A visibly empty pump basket does not prove every pipe is winterized.
7. Use antifreeze only where approved
If your winterizing plan calls for it, choose a pool-compatible product such as SPLASH Pool & Spa Antifreeze. Check the exact formulation against your equipment manufacturer’s requirements; different antifreezes are not interchangeable. Never substitute automotive engine coolant.
Follow the product label for placement and quantity. Do not dilute a ready-to-use product or assume its burst-protection rating means it stays liquid at that temperature. Antifreeze supplements an approved winterizing procedure; pouring it into the pool water is not a substitute for draining and protecting plumbing.
8. Fit the cover and plan winter checks
Install the correct cover with its specified anchors, straps, water bags, or other securing system. Follow the maker’s instructions for tension, water support, and rainwater removal. A seasonal cover is not automatically a safety cover. Keep barriers secure and never allow anyone onto the cover.
Check periodically for displaced hardware, debris, drainage problems, and changing water levels. Photograph the finished equipment area and record where you stored accessories.
Common closing mistakes
- Covering dirty or unbalanced water.
- Mixing chemicals or ignoring label waiting periods.
- Guessing the water level or chemical dose.
- Leaving trapped water in equipment or overlooked lines.
- Installing a cover and forgetting winter inspections.
Your quick closing checklist
Clean; test and balance; complete compatible treatments; set the approved water level; drain and protect equipment and lines; use approved antifreeze if required; secure the cover; label stored parts; schedule winter checks.
