House filter replacement: when to do it, how to do it, what it costs

Advertised prices, verified

How to replace a whole-house filter cartridge

1. Shut off and depressurize. Close the inlet valve ahead of the housing, and the outlet valve too if you have one, then press the red pressure-relief button on the housing cap or open a downstream tap until flow stops. Skipping relief is why sumps fight back and why water goes everywhere when they finally give.
2. Open the sump and remove the old cartridge. Use the housing wrench to turn the sump loose, keep a bucket underneath because it is full of water, and lift the old cartridge out. Note its orientation and model number before it goes in the trash, and take the chance to look at what it caught: heavy rust or sand is diagnostic information.
3. Clean, lubricate and reseat the o-ring. Wipe the sump out, inspect the o-ring for nicks and flattening, and give it a light coat of food-grade silicone grease before seating it back in its groove. Most leaking housings are o-ring problems, and most o-ring problems come from dry reassembly or a ring that was due for replacement.
4. Install the new cartridge and restore pressure slowly. Seat the new cartridge on the standpipe, thread the sump on hand-tight plus a small turn with the wrench, then open the inlet valve slowly with a downstream tap cracked so air escapes. Check for weeping around the sump over the next day, and write the date on the housing or the new cartridge.

When a house filter replacement is actually due

The clearest signal is pressure loss across the whole house at once: a sediment cartridge that has loaded up throttles everything downstream, and showers are usually where it gets noticed first. For carbon cartridges the signal is the return of chlorine taste or odor at the taps. Either symptom means the cartridge is done regardless of what the calendar says.

Absent symptoms, follow the interval and capacity the cartridge manufacturer prints, and shorten it if your water runs dirty. Well supplies after heavy rain, older municipal mains and construction in the neighborhood all load a cartridge faster than the rating assumes. If a fresh cartridge clogs unusually fast, that is a reason to test the supply; our well water testing guide covers what to look for.

DIY or hire it out: reading the table

The cartridge itself is the small number, and the table below shows the listed vendors' published prices by format and media. Doing the swap yourself means the cartridge price is the whole cost, which is why most homeowners handle routine changes once they have seen it done a single time.

Paying a service company makes sense in a few situations: a housing that has seized after years without service, no working shutoff valve ahead of the filter, a bank of multiple housings on a well system, or simply bundling the swap into an annual service visit that also checks the softener and inspects the plumbing. Compare that bundled visit price against the parts-only figure in the table to decide.

Common questions

My sump will not unscrew. What now?

Confirm the pressure is fully relieved first, because trapped pressure locks the threads. Then use the proper housing wrench with steady force, adding a strap wrench for grip. If it still will not move, stop before cracking the housing and have a service tech free it.

Do I need to sanitize the housing when changing cartridges?

Good practice, especially on well water: wipe the sump clean and rinse it with a mild bleach solution, then rinse thoroughly with clean water before the new cartridge goes in. It takes two extra minutes and keeps the housing from becoming a growth site.

Why does my new cartridge whistle or hammer?

Usually trapped air. Repressurize slowly with a downstream tap open until flow runs smooth and clear. If noise persists, check that the cartridge is the correct model and is seated square on the standpipe rather than cocked to one side.

Is the {median} figure the cartridge or the service call?

The table lists both where vendors publish them, and the $1,531 figure is the midpoint of the listed prices in that column. Parts-only and installed prices are different purchases, so compare within a column rather than across them.

Browse by system type

• Compare Water softeners on advertised prices
• Compare Salt-free softeners on advertised prices
• Compare Whole-house filters on advertised prices
• Compare Reverse osmosis systems on advertised prices
• Compare Shower filters on advertised prices
• Compare Countertop filters on advertised prices
• Compare Refrigerator filters on advertised prices
• Compare Iron filters on advertised prices