Pool Filter Repair
Most filter problems are not failures — they are maintenance that is overdue. Knowing the difference between a filter that needs cleaning, one that needs new media, and one that needs replacing saves a lot of money.
Read the pressure gauge first
Filter pressure is the single most useful diagnostic on the pad, and almost nobody records the number that makes it useful: the clean baseline.
When your filter is freshly cleaned with new media, note the pressure. That is your baseline. When pressure rises roughly 8–10 psi above it, the filter needs cleaning. If cleaning no longer brings it back to baseline, the media is exhausted.
| Reading | Meaning | Action |
|---|---|---|
| At baseline | Filter is clean | Nothing |
| 8–10 psi above baseline | Filter is dirty | Backwash or clean the cartridge |
| Will not return to baseline after cleaning | Media exhausted | Replace media |
| Very low, with weak return flow | Restriction before the filter, or a pump problem | Check baskets and pump |
| Rises very quickly after cleaning | Media channelled, or a water chemistry problem | Inspect media; check chemistry |
| Gauge reads zero always | Failed gauge | Replace the gauge — a $15 part |
The three filter types
| Type | Media life | Media cost | Filtration | Maintenance |
|---|---|---|---|---|
| Sand | 5–7 years | $150–$400 | Coarsest | Easiest — backwash |
| Cartridge | 2–4 years | $150–$600 | Good | Rinse and replace; no backwash |
| Diatomaceous earth (DE) | 3–5 years (grids) | $200–$700 | Finest | Most involved |
Common faults and costs
| Problem | Cause | Cost |
|---|---|---|
| Pressure will not drop after cleaning | Media exhausted | $150–$700 |
| Sand returning to the pool | Cracked lateral or standpipe | $200–$500 |
| DE returning to the pool | Torn grid or damaged manifold | $200–$600 |
| Leaking at the housing seam | Failed o-ring or clamp band | $80–$250 |
| Cracked housing | Age, freeze damage or over-pressurisation | Replace unit: $600–$1,800 |
| Multiport valve leaking to waste | Failed spider gasket | $100–$300 |
| Gauge reads incorrectly | Failed gauge | $15–$60 |
Repair or replace the unit?
Filter housings are simple and long-lived, so most of the time the answer is to replace the media rather than the filter.
- Replace media, keep the filter. Housing is sound, the unit is under about twelve years old, and it is correctly sized for your pump.
- Replace the unit. The housing is cracked, the clamp band or lid no longer seals reliably, or parts are no longer available.
- Replace and resize. The filter has always been undersized for the pump — an oversized pump pushing water through an undersized filter means poor filtration and short media life.
- Consider a type change. Moving from sand to cartridge eliminates backwashing and saves water, which matters in restricted areas.
What this project needs measured
Measurements are only requested when they change the price of the work you selected. Everything below is collected inside the estimator — you can enter dimensions you already know or measure as you go.
Required
No measurement required
This project is diagnosed from symptoms and equipment details rather than dimensions.
What the estimator will ask you
- Filter type: sand, cartridge or DE
- Brand and model
- Current pressure reading, and the clean baseline if you know it
- When the media was last replaced
- What the water looks like
- Photos of the filter and pressure gauge
How to read a PoolSavr estimate
- Step 1
Instant estimate
Based on your project selections and general pricing assumptions. Useful for deciding whether a project is realistic.
- Step 2
Measured estimate
Uses your pool, spa, or deck dimensions to price the work against the areas actually being resurfaced, tiled, or replaced.
- Step 3
Contractor proposal
Prepared by a licensed professional after inspecting the site. This is the only number that becomes a contract.
PoolSavr is an estimating and matching platform. We do not perform pool work ourselves — licensed local professionals do. Contractors pay PoolSavr for qualified project leads, which is how the estimating tools stay free for homeowners. A PoolSavr estimate is a planning range, never a guaranteed quote — read thefull estimate disclaimer.
Frequently asked questions
- When should I clean my pool filter?
- When pressure rises roughly 8–10 psi above its clean baseline. Record that baseline right after a clean with fresh media — without it, the gauge cannot tell you much.
- How often does filter media need replacing?
- Sand every 5–7 years, cartridges every 2–4, and DE grids every 3–5. The signal is when cleaning no longer returns pressure to baseline.
- Why is sand coming back into my pool?
- A cracked lateral or a damaged standpipe inside the filter is letting sand past. It needs the filter opened and the internals replaced, typically $200–$500. It will not resolve on its own.
- How much does a new pool filter cost?
- A complete replacement unit runs $600–$1,800 installed depending on type and size. Media or element replacement on a sound housing is much cheaper at $150–$700, and that is the more common answer.
- Which filter type is best?
- DE filters the finest, cartridge is the best balance of filtration and convenience with no backwashing, and sand is the cheapest and simplest to maintain. In water-restricted areas cartridge has a real advantage, since backwashing a sand filter uses hundreds of gallons.
Ready to see what your project costs?
Start with the work you are considering. You will get a preliminary range before anyone asks for your phone number, and you decide whether to request a contractor review at the end.