Whole-House Water Filter Guide: What You Need to Know

What a whole-house filter does

A whole-house water filter, also called a point-of-entry (POE) system, treats all water entering your home before it reaches any faucet, shower, toilet, or appliance. Every drop of water in the house passes through it. This is fundamentally different from point-of-use filters (under-sink, countertop, fridge) that only treat water at a single location.

Whole-house filtration makes sense when the problem affects your entire home, such as chlorine odor in every shower, sediment clogging appliances, or iron staining throughout the house. If your concern is limited to drinking water contaminants like lead, PFAS, or arsenic, a point-of-use system is usually more practical and cost-effective.

When you need a whole-house filter

• Chlorine or chloramine taste and odor in showers, cooking, and drinking water
• Sediment, sand, or visible particles from a well or aging municipal pipes
• Iron or manganese staining on fixtures, laundry, and appliances
• Hydrogen sulfide odor throughout the house
• Well water with multiple aesthetic contaminants
• Desire to protect appliances (water heater, dishwasher, washing machine) from sediment and scale

Types of whole-house filters

Sediment filters

Remove physical particles: sand, silt, rust, and debris. Rated by micron size. A 5-micron filter catches most visible sediment. A 1-micron filter catches finer particles but restricts flow more. Often used as the first stage (pre-filter) before other treatment.

Micron rating	What it catches	Best for
50 micron	Large sand, debris	Heavy sediment pre-filtration
20 micron	Fine sand, visible particles	General well water pre-filtration
5 micron	Silt, rust, fine sediment	Standard whole-house sediment removal
1 micron	Very fine particles, some cysts	Final polishing; may reduce flow rate

Cost: $100 to $300 for the housing. Replacement cartridges cost $10 to $30 and need changing every 3 to 6 months depending on sediment load.

Carbon filtration

The most common whole-house filter type. Activated carbon adsorbs chlorine, chloramine, volatile organic compounds (VOCs), some pesticides, and improves taste and odor. Two forms:

• Granular activated carbon (GAC): Loose carbon granules in a tank. Higher flow rates, lower pressure drop. Media lasts 3 to 5 years before replacement ($100 to $300 for media). Best for chlorine removal.
• Carbon block cartridges: Compressed carbon in a replaceable cartridge. Finer filtration and better contaminant reduction, but higher pressure drop and more frequent replacement (every 6 to 12 months). Cartridges cost $30 to $80.

For chloramine removal specifically, catalytic carbon is required. Standard activated carbon removes chloramine too slowly for whole-house flow rates.

Oxidation filters (iron and manganese)

Designed specifically for well water with iron and manganese. Media types include birm, greensand, and catalytic carbon. These systems oxidize dissolved metals into solid particles and trap them in the filter bed, which is periodically backwashed to flush out the captured material. See our iron treatment guide for detailed comparisons.

Multi-stage systems

Combine two or more filtration technologies in sequence. A typical configuration:

1. Stage 1: Sediment pre-filter (5 or 20 micron)
2. Stage 2: Carbon filter for chlorine, taste, odor, and VOCs
3. Stage 3: Specialty media for specific contaminants (KDF for heavy metals, catalytic carbon for chloramine)

Multi-stage systems cost $800 to $3,000 and provide the most comprehensive treatment short of a reverse osmosis system.

Cost comparison

System type	Upfront cost	Annual maintenance	Contaminants removed
Sediment filter	$100-300	$30-60	Particles, sand, rust
Carbon (GAC tank)	$400-1,000	$50-100	Chlorine, taste, odor, VOCs
Carbon block cartridge	$300-600	$80-200	Chlorine, taste, odor, VOCs, some lead
Oxidation filter	$800-2,000	$50-150	Iron, manganese, H2S
Multi-stage system	$800-3,000	$100-300	Multiple contaminants

What whole-house filters do NOT remove

This is important. Whole-house carbon filters do not remove:

• Total dissolved solids (TDS), including hardness minerals
• Fluoride
• Nitrate and nitrite
• Most heavy metals (lead, arsenic, chromium) unless the system includes a specific media for them
• PFAS (requires specialty media or reverse osmosis)
• Bacteria and viruses (requires UV or chemical disinfection)

If your primary concern is lead, PFAS, or other dissolved contaminants in your drinking water, a reverse osmosis system at the kitchen sink is more effective and less expensive than trying to address these at whole-house scale.

Sizing and flow rate

An undersized whole-house filter causes low water pressure throughout your home. Sizing depends on two factors:

• Peak flow rate: How much water your home uses at maximum demand (multiple showers, dishwasher, and laundry running simultaneously). Most homes need 10 to 15 gallons per minute (GPM). Larger homes may need 15 to 20 GPM.
• Pipe size: Match the filter to your main water line. A 1-inch main needs a 1-inch filter housing. Reducing pipe size at the filter creates a bottleneck.

Check the manufacturer\'s rated flow for the system at your target filtration level. A system rated at "15 GPM" often achieves that at a coarser filtration level; at finer filtration, actual flow may be lower.

Installation considerations

Whole-house filters install on the main water line after the pressure tank (for well water) or after the meter (for municipal water), but before the water heater and any water softener. Basic installation steps:

1. Shut off the main water supply
2. Cut into the main line and install the filter housing or tank
3. Add shut-off valves and a bypass valve on both sides of the filter
4. Flush the system before use

Professional installation typically costs $200 to $500 depending on plumbing complexity. Cartridge-style housings are simpler to install than backwashing tank systems.

Maintenance schedule

• Sediment pre-filter: Replace every 3 to 6 months
• Carbon cartridge: Replace every 6 to 12 months or per manufacturer\'s gallon rating
• GAC tank media: Replace every 3 to 5 years
• Backwashing systems: Automatic, but check that backwash is running on schedule monthly

Check your city\'s water quality to identify which contaminants you need to address, then choose a system matched to those specific problems. See our whole-house filter recommendations for tested products at every price point.