The consensus answer from manufacturers, guides and experienced homeowners is straightforward: change a whole-house sediment filter every 3 to 6 months in a typical home. That range is not a sales trick — it reflects how different real water is. A clean city-water home may comfortably run six months. A well pushing sand and rust may need a change in six weeks. Your cartridge and your pressure gauge tell the truth; the calendar is only a reminder.
The three signals that it is time
Pressure drop. The most reliable signal. When pressure across the housing falls by roughly 10–20 PSI compared with a fresh cartridge, the cartridge is loaded — change it even if the calendar says otherwise. A noticeable drop in shower pressure or flow at several fixtures at once is the homeowner version of the same signal.
Visible loading. A cartridge that comes out dark brown, orange with rust, or heavy with grit has done its job and is done. If it comes out nearly clean at six months, your interval can stretch a little; if it is packed at six weeks, shorten the interval or go coarser (see below).
Time. Even lightly loaded cartridges should not sit indefinitely in a damp housing. Six months is a sensible ceiling for most homes, which is also why replacement searches and multipack buying follow a 3 to 6 month rhythm.
Why yours might clog faster than your neighbour's
Heavy sediment load is the usual cause, but micron mismatch is the fixable one: a lone 1 or 5 micron cartridge on a sandy well will load in days. The fix is stepped filtration — a coarse 50–100 micron stage protecting a finer 5–10 micron stage — or a larger cartridge. Big Blue (4.5 inch diameter) cartridges hold far more dirt than slim 2.5 inch cartridges and are the standard upgrade for homes changing filters too often. Read What Micron Sediment Filter Do I Need? before ordering a finer replacement for a clogging problem.
How to change it, briefly
Shut off water to the housing, relieve pressure, unscrew the sump with the housing wrench, swap the cartridge (note its size and micron for next time), check the O-ring, and restart slowly while checking for leaks. Keep a spare on hand so a pressure drop never becomes an emergency: order replacements from Sediment Filter Replacement Cartridges or your size collection — Big Blue or Whole House. Every Hydrana cartridge is made to order and manufactured in the USA, in 10 and 20 inch lengths and 1 to 100 micron ratings.