How to Clean a Pool Pump Filter - Strainer Basket and Main Filter

The Two Filters in Your Pool System

Searching for how to clean a pool pump filter usually means one of two things - and it is worth knowing the difference before you start:

Pump strainer basket: The small removable basket inside the pump housing (the clear lid you can see-through on most pumps). It catches leaves, hair, and large debris before they reach the impeller. This needs cleaning every 1-2 weeks.

Main pool filter: The large tank (sand, cartridge, or DE) that actually filters fine particles from the water. This is serviced less often - monthly to seasonally depending on filter type.

This guide covers both, starting with the strainer basket since that is the more frequent task.

Part 1: Cleaning the Pump Strainer Basket

What you need:

• Garden hose with spray nozzle
• Soft brush (optional, for stubborn debris)
• Replacement O-ring lubricant (silicone-based)

Steps:

1. Turn the pump off. On a timer-controlled pump, switch to manual off. Do not just wait for the timer cycle.

2. Relieve suction pressure. Close the suction-side shutoff valve if your installation has one. For above-ground pools without a shutoff, move quickly once the lid is off to prevent air lock.

3. Open the strainer lid. Most lids are hand-tight with a quarter-turn. Some require a lid wrench. Turn counter-clockwise to remove.

4. Lift out the basket. Pull straight up. Have a trash bag nearby.

5. Dump the debris. Tap the basket against the inside of the lid or into a bag. Do not knock it against concrete - the mesh can crack.

6. Rinse with a garden hose. Work from the inside out to push debris through the mesh rather than packing it in. A short burst of water is usually all that is needed.

7. For stuck organic matter: Use a soft brush. Do not use a pressure washer - the force can distort the mesh or crack the plastic.

8. Inspect the basket. Look for holes, cracks in the frame, or distorted mesh. Replace if damaged - a compromised basket is not worth reusing.

9. Check and lubricate the lid O-ring. Wipe the O-ring and the lid seat clean. Apply a thin coat of silicone lubricant (never petroleum-based, which degrades rubber). Replace the O-ring if it is cracked or flattened.

10. Replace the basket and lid. Hand-tighten only. Over-tightening cracks the lid.

11. Open the suction valve and restart the pump. Watch through the clear lid as the pump primes - air bubbles should clear within 1-2 minutes as the basket fills with water.

Pool pump O-ring silicone lubricant on Amazon - a small tube lasts a full season and prevents lid-seal leaks.

Part 2: Cleaning the Main Pool Filter

The main filter is downstream of the pump. Filter type determines how and how often it is cleaned.

Sand Filter

Clean by backwashing - reversing water flow to flush trapped debris out through the waste line.

When to clean: when the pressure gauge reads 8-10 PSI above the clean starting pressure (note the baseline on your gauge after a fresh backwash).

Backwash procedure: set multiport valve to BACKWASH, run for 2 minutes until the sight glass runs clear, then set to RINSE for 30 seconds before returning to FILTER.

Full guide: How to Backwash a Pool Filter

Sand also needs a chemical deep-clean once per season to dissolve oils that backwashing alone cannot remove. Guide: How to Clean a Pool Sand Filter

Cartridge Filter

Clean by rinsing the cartridge elements with a garden hose. For a thorough clean, soak overnight in a cartridge filter cleaning solution.

When to clean: when pressure rises 8-10 PSI above baseline, or every 3-6 months as a routine.

Cartridges do not backwash - the tank must be opened and the cartridge(s) removed. Full guide: How to Clean a Cartridge Pool Filter

DE Filter

Clean by backwashing, then re-charging with fresh DE powder.

When to clean: when pressure rises 8-10 PSI above baseline.

After backwashing, add fresh DE powder through the skimmer (1 lb per 10 sq ft of filter area as a starting point). Full guide: How to Backwash a DE Pool Filter

Signs the Pump Strainer Basket Needs Cleaning Now

• Pressure gauge reading is higher than your normal baseline
• Reduced return jet flow (water trickling rather than jetting from returns)
• Pool takes longer than usual to turn over and clear
• Pump sounds labored or cycles off on thermal overload
• Visible debris through the clear pump lid

Do not wait until the basket is full - cleaning it at the one-third mark maintains flow and reduces pump wear.

Related Guides

• Pool Filter Pressure Too High - diagnosing high pressure
• How to Backwash a Pool Filter - full backwash procedure
• How Long Does a Pool Filter Last - lifespan for all filter types
• Pool Filter Maintenance Guide - full seasonal schedule