A whole home sediment filter sits where the supply enters the building and takes suspended particles out before they reach anything else. It is the cheapest protective stage you can fit and the one most often specified wrongly, because buyers pick the finest cartridge available and then live with poor pressure. Sizing is about peak flow and staging, not about choosing the smallest micron number on the shelf.
Size for peak flow, not for the house
The number that matters is the peak simultaneous demand: two showers running while a washing machine fills is a realistic worst case in a family home, and that is the flow the filter has to pass without an unacceptable pressure drop. Bedroom counts and square footage are proxies that mislead. Look at the vendor's published service flow rating for the housing and cartridge combination and choose one that carries your peak comfortably rather than exactly. A filter running at the top of its rating from new has nowhere to go as it loads, so the pressure complaint arrives within weeks.
Stage the filtration instead of going straight to fine
One fine cartridge doing all the work is the classic mistake. It blinds off quickly on any real sediment load, drops pressure across the house, and costs more in cartridges than the alternative. Put a coarse cartridge first to take the bulk of the material, then a finer one after it to polish. The coarse stage protects the fine stage, the fine stage lasts several times longer, and the combined pressure drop of two lightly loaded cartridges is lower than one heavily loaded one. This is the same logic that puts a sand separator ahead of everything on a well that pumps grit.
Cartridge housing or backwashing tank
A big housing with a replaceable cartridge is cheap to install, needs no drain and no power, and suits a modest, predictable sediment load. A backwashing media tank costs more up front, needs a drain that can accept the backwash flow and a socket for the valve, and repays it where sediment is heavy or seasonal, since it cleans itself instead of consuming cartridges. Vendors publish both formats with service flow ratings you can compare directly. Where a well throws grit after heavy rain or when the pump starts, the tank usually wins on running cost within a couple of years.
Install it so you can maintain it
Fit isolation valves either side and a full bypass so a cartridge change does not mean shutting the house down, and leave clearance below the housing to drop the sump without dismantling anything. A pressure gauge before and after the filter turns guesswork into a reading: a widening gap tells you the cartridge is loading well before anyone complains about the shower. Keep spare O-rings and food-safe grease with the spare cartridges. If you are budgeting the sediment stage alongside carbon or softening, our whole home water filter cost guide sets out how installers group them.
Questions people ask about whole home sediment filter
What micron rating should a whole house sediment filter be?
It depends on your water, but staging a coarse cartridge ahead of a finer one works better than a single fine rating, which blocks quickly and costs pressure.
Will a sediment filter improve taste or smell?
Only if the problem is particulate. Chlorine taste, musty odour and sulfur smell are chemical or dissolved-gas problems that need carbon or oxidation treatment.
How do I know when to change the cartridge?
By the pressure difference across it rather than by a date. Gauges either side give an honest reading; without them, falling pressure at the taps is the late signal.
Does a sediment filter go before or after the pressure tank?
On a well, fitting protection ahead of the pressure tank keeps grit out of the tank and controls, though many installations place the cartridge stage after it for easier access.