Water filtration system maintenance comes down to a handful of dated tasks, and every one of them exists because a filter that is full stops protecting anything downstream of it. Sediment cartridges clog, carbon exhausts silently, membranes scale, softener salt runs out and UV lamps dim. This page lays out the rhythm by component so the whole system can go on a single calendar.
Cartridge stages: the ones that clog and the ones that exhaust
Sediment filters fail loudly: pressure drops, flow weakens, and the housing shows the dirt when you open it, so the house itself reminds you. Carbon fails silently, which is the dangerous kind: exhausted carbon passes chlorine and everything else it was catching with no change in flow at all, so carbon changes must run on the manufacturer's published schedule rather than on symptoms. Date every cartridge with a marker at install, keep spares on the shelf so a change never waits on shipping, and when you open a housing, inspect the O-ring and lubricate it, since most post-service leaks are a pinched or dry O-ring rather than a real fault.
Softeners: salt, resin and the iron problem
A softener asks for salt in the brine tank on a steady rhythm, a check for salt bridging where a hard crust hides an empty tank beneath, and an occasional look at the brine tank for sludge. The resin bed itself lasts years, but iron is its enemy: Penn State Extension notes that a softener can handle dissolved iron only under the right conditions, with pH above 6.7 and dissolved iron under 5 mg/L, and that iron which has already oxidized fouls the resin instead. On iron-bearing wells that means keeping the upstream iron filter healthy is itself softener maintenance, and a resin cleaner product can recover a bed that staining has begun to slow.
Membranes, UV lamps and the annual walk-around
Reverse osmosis membranes are replaced on a multi-year cycle, best confirmed by comparing feed and output TDS readings, since a narrowing gap is the membrane telling you it is done. UV lamps are the opposite of intuitive: the bulb keeps glowing long after its germicidal output has decayed, so lamps are replaced on the published schedule, not when they fail, and the quartz sleeve gets wiped clean at the same visit. Once a year, walk the whole train: check for weeps at fittings, confirm the bypass valves still turn, and flush any backwashing unit manually. Well owners should pair this with the testing rhythm in our well water filtration system guide.
Questions people ask about water filtration system maintenance
How do I know when a carbon filter is exhausted?
You usually cannot tell by taste or flow, which is the trap. Exhausted carbon passes contaminants at full flow, so carbon stages are changed on the published schedule, not on symptoms.
Why is my softener full of salt but the water feels hard?
Check for a salt bridge: a hardened crust can hold its shape while the tank beneath is empty, so the brine never forms. Break the crust and the next regeneration usually restores softening.
Do UV lamps really need replacing while they still light up?
Yes. Germicidal output decays long before the visible glow does, so a lamp on its original bulb past the published life is disinfecting far less than it appears to.