Why the Filter Matters More Than People Think
The filter is the one piece of pool equipment that gets ignored until the water goes cloudy. A dirty filter makes the pump work harder, cuts circulation, and lets a small chemistry problem turn into a green pool. Cleaning it on time is the cheapest maintenance you can do.
How you clean it, and how often, depends on which of the three filter types you have.
Cartridge vs. Sand vs. DE
| Cartridge | Sand | DE (Diatomaceous Earth) | |
|---|---|---|---|
| How it's cleaned | Remove and hose off | Backwash | Backwash + recharge with DE powder |
| Routine clean interval | Every 2–6 weeks in season | Backwash every 2–4 weeks | Backwash every 4–6 weeks |
| Deep clean | 1–2 times per season | Chemical clean once a year | Full teardown 1–2 times per year |
| Media replacement | Cartridges every 1–3 years | Sand every 3–5 years | Grids every 5–10 years |
| Filters down to | ~10–20 microns | ~20–40 microns | ~3–5 microns |
Cartridge filters are the most common on newer residential pools because there's no backwash line and no wasted water. Sand is the simplest. DE filters the finest but takes the most work.
The Pressure-Gauge Rule
You don't clean on a calendar. You clean when the gauge says so.
- 1Note the pressure reading right after a clean filter is installed and the pump is running. That's your clean pressure. Write it on the filter with a marker.
- 2Check the gauge weekly.
- 3When the reading is 8–10 psi above clean pressure, it's time to clean or backwash.
A pool with a lot of trees, heavy swimmer load, or a recent algae problem will hit that number faster. A screened pool in Florida might go six weeks. A pool under oak trees in Texas might go two.
Low pressure is a different warning. If the gauge reads well below clean pressure, something is blocking flow before the filter: a full skimmer basket, a full pump basket, or a suction-side air leak.
How to Clean Each Type Yourself
Cartridge:- Turn off the pump, release pressure, open the tank
- Pull the cartridge and hose between every pleat, top to bottom
- Check for torn pleats or a cracked end cap
- Once or twice a season, soak overnight in a filter-cleaning solution to remove oils and scale, then rinse
- Set the multiport valve to Backwash, run 2–3 minutes until the sight glass runs clear
- Set to Rinse, run 30 seconds
- Return to Filter
- Once a year, run a sand-filter cleaner through the system to break down oils the backwash leaves behind
- Backwash the same way as sand
- Add fresh DE powder through the skimmer to recoat the grids
- Once or twice a year, open the tank, pull the grid assembly, hose every grid, and inspect for tears
What a Pro Filter Clean Costs
Most weekly service plans include routine cartridge rinses and backwashing. The deep clean is usually a separate line item.
| Service | Typical Price (2026) |
|---|---|
| Cartridge deep clean (soak and rinse) | $50–$125 |
| Sand filter chemical clean | $75–$150 |
| DE filter teardown and grid clean | $100–$200 |
| Sand replacement (labor + sand) | $250–$500 |
| Cartridge replacement (parts + labor) | $100–$400 |
| DE grid set replacement | $300–$700 |
If you're on a weekly plan, ask whether deep cleans are included. Some companies do one or two a year as part of the rate; others charge each time. See How Much Does Pool Service Cost in 2026 for how filter work fits into monthly pricing.
When to Replace Instead of Clean
- Cartridges: when the pleats are frayed, the fabric is stiff and gray after a soak, or clean pressure keeps creeping higher after every clean. Most last 1–3 years.
- Sand: when it clumps, channels, or pressure rises fast right after backwashing. Figure 3–5 years, sooner in hard-water areas.
- DE grids: when you see DE powder returning to the pool (a torn grid) or the fabric is worn through. Grids last 5–10 years.
DIY or Hire It Out?
Routine rinsing and backwashing are easy and worth learning. The deep cleans, grid teardowns, and sand changes are where people tend to hire a pro, mostly because they're messy and the reassembly has to be right. If you already have weekly service, make sure filter cleaning is on the checklist. If you don't, see Pool Maintenance Schedule: Weekly, Monthly & Seasonal for where filter work fits in.
Browse Pool Service Companies by City
Some of the most-searched markets on Pool Service Scout:
- Sarasota, FL · Naples, FL · Fort Myers, FL · Tampa, FL · Ocala, FL
- Lake Havasu City, AZ · Corpus Christi, TX · Fort Worth, TX · San Antonio, TX
- Bakersfield, CA · Fresno, CA · Oklahoma City, OK · Tulsa, OK
Or by state: Florida, Texas, Arizona, California, Oklahoma, South Carolina.
Bottom Line
Watch the gauge, clean at 8–10 psi over clean pressure, and deep clean once or twice a season. If you'd rather not, find a pool service company near you that puts filter cleaning on the weekly checklist.