Why Pool Filter Cleaning Matters (and How Often to Do It)
By Imperial Valley Pool Services · Updated 2026-10-23
A clogged filter can't clean the water, forces your pump to work harder and lets algae take over. Clean a cartridge filter when its pressure gauge rises about 8–10 psi above its clean reading, and backwash sand or DE filters at the same point. Dusty desert pools often need it more often than the manual suggests.
The filter is the pool's kidney. Everything the skimmer and pump pull in ends up there, and when it is full, the whole system suffers.
What happens when a filter is dirty
- Water looks cloudy even when chemicals are balanced.
- Flow slows down, so chlorine isn't spread through the pool.
- The pump works against higher pressure, which shortens its life and raises power use.
- Algae gets a head start, because the filter can't remove it.
- Cleaners and skimmers lose suction.
Know your filter type
Cartridge
Pull the cartridges and rinse them with a hose, working between the pleats. Several times a year, soak them in a filter cleaner to dissolve oils and minerals. Replace them when the pleats are cracked, flattened or no longer come clean. That is commonly every few years.
Sand
Backwash when pressure rises about 8–10 psi over the clean pressure, then rinse. Sand wears smooth and loses its grip over the years. Most manufacturers recommend replacing it every few years.
DE (diatomaceous earth)
Backwash, then add fresh DE through the skimmer. DE filters catch the finest particles but need a periodic full teardown and grid cleaning.
Signs it's overdue
- Pressure gauge is 8–10 psi above its clean-filter reading.
- Water won't clear even though chlorine and pH are right.
- Weak return jets or a cleaner that stalls.
- The pump is louder than usual.
Desert dust changes the schedule
Wind and dust storms send fine silt into the pool and straight into the filter. After a storm, check the pressure and rinse early. Our technicians check filter pressure on every visit, and a deep cleaning is part of how we keep pools clear. See our services.
Frequently asked questions
How often should a pool filter be cleaned?
Based on pressure, not the calendar. When the gauge reads 8–10 psi above its clean reading, clean or backwash. Many Imperial Valley pools need this every few weeks in dusty or heavy-use periods.
Can I clean a cartridge filter with a pressure washer?
Avoid high-pressure sprays. They can damage the pleats and shorten the life of the cartridge. Use a garden hose with a gentle spray.
How do I know whether to clean or replace the cartridge?
If pleats are cracked or flat, or the cartridge doesn't recover pressure after a thorough cleaning, replace it.