Whole House Water Filters

A whole-house water filter (also called a point-of-entry or POE system) treats all the water entering your home before it reaches any tap, shower, or appliance. Unlike under-sink or pitcher filters that treat water at a single point, a whole-house system means every faucet delivers filtered water, including showers, bathtubs, laundry, and outdoor spigots.

The most common type uses activated carbon media to remove chlorine, chloramine, sediment, and volatile organic compounds (VOCs). More advanced systems add specialized media for specific contaminants. If your primary concern is chlorine taste and odor or you want a baseline layer of filtration for your entire home, a whole-house carbon filter is usually the starting point.

How Whole-House Carbon Filtration Works

Water enters the filter tank and flows through a bed of granular activated carbon (GAC) or a carbon block. The carbon adsorbs chlorine, chloramine (if catalytic carbon is used), certain pesticides, herbicides, VOCs, and sediment. The treated water then flows to your home's plumbing system at full household pressure.

The key variable is contact time. Water needs to spend enough time in contact with the carbon for adsorption to occur. Systems with larger tanks and slower flow rates provide longer contact time and better filtration. A system running at its maximum flow rate will filter less effectively than one operating below its rated capacity.

Catalytic carbon is an important distinction. Standard GAC removes free chlorine very effectively but has limited impact on chloramine. If your utility uses chloramine (about 20% of US systems do), make sure the system specifies catalytic carbon or a chloramine-rated media. Your city's water report will confirm which disinfectant is used, or check our database.

What Whole-House Filters Remove

A standard carbon-based system reliably addresses chlorine and chloramine (with catalytic carbon), sediment and particulates, VOCs including some industrial solvents, some pesticides and herbicides, and unpleasant taste and odor.

Some systems add specialized media stages for iron and manganese (oxidizing media like birm or greensand), hydrogen sulfide (the rotten egg smell), and PFAS (specialized carbon or ion exchange media). Multi-stage systems that combine carbon with these additional media cost more but handle a broader range of issues.

What Whole-House Filters Do NOT Remove

Standard carbon filtration does not remove hardness minerals (you need a water softener or conditioner for that), dissolved solids including TDS, nitrate, arsenic, or fluoride (you need reverse osmosis for these), or bacteria and viruses (you need UV disinfection or a membrane system).

Lead removal depends on the specific system. Some whole-house systems with fine carbon block media can reduce lead, but because lead often enters water from the last few feet of plumbing inside the home, a point-of-use filter at the drinking tap is more effective for lead specifically. See our Lead guide for the full picture.

Sizing Your System

Whole-house filters are sized by two factors: flow rate (GPM) and filter capacity (gallons before replacement).

Flow rate must meet your home's peak demand. A household with 1 to 2 bathrooms typically needs 10 to 15 GPM. Homes with 3+ bathrooms should look for 15 to 20 GPM. Undersizing causes noticeable water pressure drops when multiple fixtures are running simultaneously.

Filter capacity determines how often you replace the media or cartridge. Higher-capacity systems (500,000 to 1,000,000 gallon ratings) use larger tanks with replaceable media beds that last 3 to 5 years. Cartridge-based systems use replaceable filters that last 3 to 12 months and are typically less expensive upfront but have higher ongoing costs.

Cost Breakdown

A cartridge-based whole-house system costs $100 to $400 for the housing and $40 to $150 per cartridge replacement every 3 to 6 months. A tank-based system with replaceable media costs $500 to $2,000 for the system and $100 to $300 for media replacement every 3 to 5 years. Professional installation runs $200 to $500 in most markets.

Total first-year cost: $400 to $2,500 depending on system type. Ongoing annual cost: $80 to $300 for cartridge systems or $30 to $100 for tank-based systems.

Installation Requirements

A whole-house filter is installed on the main water line after the water meter and before the water heater. You need access to the main water line (typically in the garage, basement, or utility closet), enough space for the filter housing or tank, and a bypass valve (most systems include one) for maintenance.

No drain connection or electrical outlet is required for basic carbon systems. If you are adding a pre-filter for sediment (recommended if you have well water or high sediment), it installs upstream of the main filter.

Combining with Other Systems

A whole-house carbon filter is frequently the first layer in a multi-system setup. Common combinations include carbon filter plus water softener (for homes with both chlorine and hard water), carbon filter plus UV disinfection (for well water or bacteria concerns), and carbon filter plus under-sink RO (for whole-house chlorine removal plus point-of-use contaminant removal at the kitchen tap).

When combining with a water softener, the carbon filter typically goes first in the line. It removes chlorine before the water reaches the softener, which protects the softener resin from chlorine degradation and extends its lifespan.