SplashLens
Closing / filter

How to winterize a pool filter

Winterizing a pool filter means draining trapped water and following that model's storage steps, not only switching the pump off. Identify cartridge, sand, or DE, relieve pressure, photograph every drain plug and removed element, and use the installed manual because Hayward's public closing steps for cartridges and DE grids do not cover every sand filter.

Last reviewed October 12, 2026 · Reference only; the installed filter manual controls.

Run Closing Mode freeClosing Season hub

Document the filter close

  1. Identify the filter type and open its winterizing section.
  2. Shut off the pump and relieve pressure before opening the tank.
  3. Photograph each model-specified drain plug after the tank is drained.
  4. Record removed cartridges or grids, where they are stored, and any element left in place.

Hayward's public closing article says to drain the pump, filter, chlorinator, and heater, then remove and clean DE grids and cartridge elements. Pentair's System 3 sand-filter manual tells the reader to open the air-release valve, open system valves, set the multiport between positions, remove drain plugs, drain piping, and protect the filter from freezing. Those are examples, not a shared procedure. A different cartridge, sand, or DE model can use different plugs, valves, and storage rules.

Stop before compressed air or an open tank

Relieve pressure and follow the model's opening steps before removing a lid or clamp. Pentair's System 3 modular DE manual warns that purging with compressed air can separate components and cause severe injury, and it limits air purging to a low-pressure, high-volume blower when that method is used. Do not apply that warning, or any other model's air method, to a filter that was not identified.

Proof to capture

  • Filter model plate, clean and dirty pressure if still readable, and valve position.
  • Air-relief and each drain plug after water has left the tank.
  • Cartridge or grid count, condition, and where the elements will be stored.
  • Any sand, laterals, or manifold left in place, plus the spring restart note.

Questions

Does turning the pump off winterize the filter?

No. Water can stay in the tank, valve, and piping after the pump is off. The installed filter manual controls draining, element removal, and storage.

Can one drain procedure cover cartridge, sand, and DE filters?

No. Hayward's public closing article treats cartridge and DE elements differently from a drained tank, and a Pentair sand-filter manual uses its own valve and drain-plug steps. Use the installed model.

Sources

Related field pages

Identify the element before ordering a replacement: filter cartridge or DE grid proof. The same close also needs the pump, heater, and salt cell pages.