How often to clean a pool filter is the question every new pool owner in the Valley asks, and the honest answer is: when the gauge tells you. A filter in a quiet January backyard can go a long time between cleanings. The same filter in July, with kids in the water every afternoon and a dust storm rolling through, may need attention within days. This guide gives you the pressure rule, a season-by-season schedule for Phoenix, and the things that shorten the wait.
Phoenix Pool Cleaning Pro is a free phone line, not a pool company. If you would rather have a pool company keep the filter on schedule, call (623) 240-0428 any hour and you will be put through to an independent local pool service company that quotes and does the work itself.
The pressure rule behind every pool filter cleaning schedule
Your filter has a pressure gauge, usually on top of the tank. As the filter holds more dirt, water has a harder time getting through and the needle climbs. How fast that happens changes with how many people swim, how long the pump runs and the weather.
The common rule of thumb is to backwash or clean when pressure rises about 8 to 10 psi over the clean starting pressure. Angi's filter cleaning guide uses that figure, and Pool and Spa News reports that many technicians backwash at that rise. Your filter's manual may give its own number. Either way the habit is the same: know your clean number, then watch for the rise.
Keep a simple pressure log
- Write down the clean number. Right after a cleaning, with the pump at its usual speed, note the reading. A strip of tape on the tank or a note on your phone works.
- Read the gauge at the same pump speed each time. Variable-speed pumps show different pressures at different speeds, so compare like with like.
- Check once a week, and after storms. A weekly glance shows the trend; a check after a haboob or heavy rain catches a sudden jump.
- Act at the rise, not at a date. When the reading sits about 8 to 10 psi over the clean number, it is time.
- Watch the clean number itself. If it creeps higher after each cleaning, the media may be wearing out or the plumbing may need a look.
A falling reading is a different signal. Pressure lower than your clean number usually means the pump is not getting enough water, often because a basket is full or the water level is low. The pool filter cleaning page has a symptom table for low and high pressure and what a professional clean involves for each filter type.
A seasonal pool filter cleaning schedule for the Valley
Use the gauge to decide. Use this table to know when to look harder. The intervals are general starting points for a home pool, not rules, and your own pressure log will soon tell you more than any chart.
| Season in the Valley | What loads the filter | Cartridge | DE | Sand |
|---|---|---|---|---|
| Spring (March to May) | Wind, blossoms and pollen from yard trees, more swimming as the water warms | Check pressure weekly; clean at the rise | Backwash at the rise; open and clean the grids before summer | Backwash at the rise |
| Early summer (June) | Heavy swimming, sunscreen and body oils, long pump run times in the heat | Expect cleanings closer together | Watch for short runs between backwashes | Backwash more often; watch for cloudy water |
| Monsoon (June 15 to September 30) | Dust storms, blown leaves and debris, rain runoff from decks | Check after every storm; a single haboob can push pressure up fast | Backwash after storms that raise pressure | Backwash after storms that raise pressure |
| Fall (October and November) | Leaves from deciduous trees, fewer swimmers as nights cool | Clean once the storm season ends | A good time to open the filter and clean the grids after the storms | Backwash at the rise |
| Winter (December to February) | Light use, shorter pump run times, occasional winter rain | Cleanings spread far apart | Backwash only at the rise | Backwash only at the rise |
The monsoon dates are the National Weather Service's official season. The Weather Service's Phoenix office reports that in an average year one to three large dust storms move into the Phoenix area, mostly from the southeast. Normal daily highs at Sky Harbor sit above 100 degrees in June, July and August under the 1991 to 2020 normals, which means long pump run times and more evaporation for the filter to work through.
When to clean a pool filter cartridge versus DE or sand
The pressure rule applies to all three filters, but each type reaches it differently and is cleaned differently.
Cartridge
A large cartridge filter on a lightly used pool can go a long time between cleanings, while a small one on a busy pool may need it every few weeks. Angi's guide says cartridge filters generally need cleaning several times a season, and HomeGuide says the cartridges themselves usually need replacing every two to three years. That spread is exactly why the gauge matters more than any number of weeks.
DE
A DE filter is backwashed when pressure rises, then given fresh powder. Backwashing does not remove everything, so the grids still need to be taken out and cleaned from time to time. A pool technician can tell you how often your filter's grids need that fuller cleaning, based on how fast the pressure returns after a backwash. Spent DE has to be handled and disposed of under your city's rules.
Sand
A sand filter is backwashed at the rise. The sand itself wears out over years, not weeks. If backwashing stops bringing the pressure back down, or the time between backwashes keeps shrinking, ask a pool technician to check the sand and the laterals under it.
Backwash water and cartridge rinse water carry dirt and chlorine, and Valley cities restrict where they may go. In Phoenix, the Water Services Department asks residents to keep pool water out of the street and alley, and to use the sewer cleanout or their own landscaping. Other cities have their own rules, collected in the guide to draining a pool in Arizona.
What shortens the time between cleanings
If your filter needs cleaning far more often than your neighbor's, one of these is usually the reason:
- A dust storm or heavy rain. Dirt, leaves and runoff from the deck go straight to the skimmer and the filter.
- Algae. Even a faint green tint loads a filter fast, and clearing a green pool can mean cleaning the filter several times in a few days. See why pools turn green.
- Heavy swimming. Sunscreen, lotions and body oils coat filter media. A busy summer weekend shows up on the gauge.
- Hard water and scale. City of Phoenix tap water is hard, as its annual water quality report shows, and minerals can build up in filter fabric over time.
- A filter too small for the pump. Pool & Spa News notes that short runs between cleanings often mean too much flow through the filter, so the filter may be undersized or the pump too powerful.
Some habits lengthen the time between cleanings. Empty the skimmer and pump baskets often, so leaves never reach the filter. Brush and skim before vacuuming so the coarse debris comes out in the net. Keep the chlorine steady: the CDC recommends at least 1 part per million of free chlorine in a home pool and a pH of 7.0 to 7.8. Water that is properly sanitized does not grow the algae that clogs a filter. Test with a home kit and follow the product labels. Never mix pool chemicals with each other, store them apart in a dry, shaded spot out of children's reach, and leave acid work to a professional.
Signs it is time now, whatever the schedule says
- The gauge reads about 8 to 10 psi over your clean number.
- The return jets push noticeably less water than usual.
- The water looks dull or hazy even though chlorine tests in range.
- A dust storm, heavy rain or a burst of leaves just went through.
- You are finishing a green pool recovery.
Leave the filter closed if you are unsure. Never open a filter lid or clamp with the pump running. Turn the pump off and release the pressure at the air relief valve first. A breaker or GFCI that trips can be reset once; if it trips again, stop and call a pool technician. Keep children away from the equipment pad and from any pool whose bottom you cannot see.
Letting a pool company keep the schedule
Many weekly pool service plans in the Valley include filter cleaning at set intervals, while others charge for it as a separate visit. When you talk to a company, ask how often the filter is cleaned under the plan, whether that changes in monsoon season, and whether they will tell you the before and after pressure. The pool cleaning and weekly maintenance page explains what a weekly visit covers, and the pool service cost guide shows published price ranges.
Filter cleaning is generally routine service. Replacing a filter, its valves or plumbing is repair work, and for that the ROC license check applies.
Check the license first. Arizona's Registrar of Contractors (ROC) licenses contractors, and its residential classifications include R-6, Swimming Pool Service and Repair. Repairs, equipment replacement and resurfacing generally call for a licensed contractor; whether a cleaning-only service needs a license is not spelled out, so ask the ROC if it matters to you. Ask the company for its ROC license number and look it up on the ROC contractor search (opens in a new tab) before work begins. The line does not check this for you.
Not sure when the filter was last cleaned? Call any hour, say what kind of filter you have and what the gauge reads, and you will be put through to a local pool company.
- Call the numberAn automated assistant answers (623) 240-0428 day or night, weekends included.
- Describe the poolSay what is going on: cloudy or green water, a pump that hums, a heater that will not fire, scale on the tile, and which part of the Valley you are in.
- Get put throughThe call is transferred to an independent, locally owned pool service company, which hears a short summary of the problem before it picks up.
- Deal with them directlyThat company looks at the pool, quotes, does the work and bills you. If it cannot answer, your name, number, area and problem are passed along so it can call you back.
About this line: Phoenix Pool Cleaning Pro is a free phone line, not a pool company. It answers your call and connects you with an independent local pool service company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. You never pay the line. See how the line works.