Sediment Filter

A sediment filter is a water filter that removes suspended particles — sand, silt, rust flakes, pipe scale, and organic debris — from water before it reaches fixtures or other filtration equipment. Sediment filters are the first line of defense in any whole-house water treatment system, protecting reverse osmosis membranes, water softeners, and appliances from particle damage.

How sediment filters work

Water passes through a filter medium — a spun polypropylene fiber cartridge, pleated polyester, or ceramic — that physically traps particles above a certain size threshold. The filter rating (measured in microns) indicates the smallest particle reliably captured: 5-micron filters catch particles down to about the width of a red blood cell; 50-micron filters catch larger sand and silt particles.

Filter ratings

• 50–100 micron: pre-filters for well water with significant sediment; protects softeners and whole-house systems
• 25–50 micron: general whole-house sediment filtering for city water
• 5–10 micron: pre-filter before RO or carbon filtration; used where fine particles, rust, or scale are a concern
• 1 micron: high-precision filtration, typically just before point-of-use RO systems

Installation and maintenance

Whole-house sediment filters install on the main supply line after the meter, before the water heater and distribution lines. The filter housing has a clear bowl for monitoring cartridge loading. Cartridges clog progressively — a sudden drop in water pressure throughout the house often indicates a fully loaded sediment filter cartridge. Replacement frequency: every 3–12 months depending on water quality and filter rating. Cartridges cost $5–$20.

Well water considerations

Homes on private wells often need more aggressive sediment filtration — a two-stage system (a 50-micron bag filter followed by a 5-micron cartridge filter) before the pressure tank, water softener, and UV treatment system protects the entire downstream treatment chain from rapid clogging.