Water Filtration
Updated November 6, 2026
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Safety
Shut off the water supply to the filter or filtration system before removing any housing, cartridge, or fitting. Relieve pressure by opening a nearby faucet after closing the supply valve, especially on tanks and canister systems. Never drink water that smells like fuel, sewage, or chemicals — stop using it and contact the local water authority or a lab for testing. Keep electrical components, such as UV lamps or booster pumps, dry and disconnect power before servicing. Do not overtighten housings or fittings when reinstalling; cracked housings can burst under line pressure. If a filter housing is leaking near electrical panels or outlets, shut off power to the area before doing anything else.
Before the visit
Locate the make and model of the existing water filtration system, usually printed on the housing or head unit. Note any changes in water taste, odor, color, or pressure and when they started. Check when the filter cartridge was last changed, if known, and whether replacement cartridges are on hand. Clear access to the filter location — under-sink cabinets, basements, or utility rooms — so the technician can work safely. Have recent water test results available, if any, since they guide equipment recommendations. Confirm an adult will be home during the appointment window and note where the main water shutoff valve is located.
Repair vs replace
The water filtration system is leaking from fittings, O-rings, or the housing but the unit is otherwise in good condition. Water pressure drops noticeably when flowing through the filter and cleaning or flushing has not helped. A bypass valve, diverter, or faucet connector is damaged or seized. The system keeps producing cloudy water after a cartridge change, suggesting an air lock or seating problem. A UV lamp, pump, or control valve on the filtration system stops functioning but the housing and plumbing are sound. A whole-house water filtration tank cycles abnormally or fails to backwash correctly.
When to replace
The filter housing is cracked, warped, or has burst seams that cannot be sealed reliably. The water filtration system is old, uses discontinued cartridges that are hard to source, and repairs cost close to a new unit. Water quality tests still show contaminants after the system runs properly, meaning the equipment is undersized for the water supply. A household's needs have changed — for example, moving from a point-of-use filter to whole-house water filtration for better coverage. Repeated leaks or cartridge failures point to worn valve heads or degraded plumbing connections throughout the unit. A commercial water filtration system no longer keeps up with demand despite fresh cartridges and proper service.
Common issues
| Symptom | Likely causes | Safe check | Stop when |
|---|---|---|---|
| Water tastes or smells like chlorine or chemicals | Exhausted carbon cartridge, cartridge installed past its rated capacity, or undersized filtration media for the chlorine level in the supply. | Note when the cartridge was last replaced and compare the date to the rated service life printed on the filter or in the manual. | The taste is accompanied by a fuel or solvent odor, which can indicate contamination that requires immediate professional testing. |
| Cloudy or discolored water after the filter | Air trapped in new cartridges, loose or damaged O-rings letting unfiltered water bypass, or sediment breaking through spent media. | Fill a clear glass and let it sit for a few minutes; air bubbles clear from the bottom up, while sediment settles to the bottom. | The water is brown, rusty, or contains visible particles that do not settle, which suggests pipe corrosion or a media failure needing a technician. |
| Sudden drop in water pressure at filtered taps | Clogged cartridge at end of life, sediment buildup in prefilters, a kinked supply line, or a partially closed shutoff valve after recent work. | Compare flow at a filtered faucet versus an unfiltered one to confirm the restriction is in the filtration system, and verify supply valves are fully open. | Pressure drops across the whole property at once, indicating a main line or supply issue rather than the filter. |
| Leaking filter housing or fittings | Worn O-rings, cross-threaded housings, cracked canisters from overtightening, or degraded tubing on quick-connect fittings. | Dry the area, place a towel under the unit, and check periodically to see whether water reappears and from which point. | Water is spraying, pooling near electrical outlets, or the leak worsens quickly — shut off the supply and call for service. |
| Filter warning light or indicator stays on after a cartridge change | Indicator not reset, an incorrectly seated cartridge, or a flow sensor that is dirty or failing. | Follow the manual's reset procedure and reseat the cartridge, listening for the click that confirms proper seating. | The indicator stays lit after a correct reset and reseating, since a faulty sensor can mask real filter exhaustion. |
| Whole-house filtration tank not backwashing or regenerating | Failed control valve, clogged injector, incorrect programming after a power outage, or a stuck bypass valve. | Check the control head display or settings against the manual and confirm the bypass valve is fully in the service position. | The tank is leaking around the base or the control head shows an error code that persists after a power cycle. |
| Scale buildup returning on fixtures despite filtration | Exhausted softening or scale-reduction media, a system sized too small for household hardness, or a bypass allowing untreated water to mix in. | Check whether scale returns only on filtered lines or throughout the property, and note the last media or cartridge replacement date. | Hardness comes back suddenly and heavily, which often means the media has fully depleted and the system needs service or replacement media. |