How much does a whole-house water filter cost?

A certified whole-house carbon system typically costs $1,500 to $3,500 installed. An under-sink Reverse Osmosis system for drinking water costs $400 to $800 installed. Prices vary based on home size, water chemistry, and local plumbing rates.

Granular Activated Carbon (GAC) absorbs chemicals and is great for whole-house filtration but requires frequent filter changes. Reverse Osmosis (RO) forces water through a microscopic membrane, removing >99% of contaminants including PFAS and heavy metals, but is usually only installed at the kitchen sink because it is slow and wastes water.

A professionally installed water softener typically costs $1,200 to $3,000. Grain capacity (sized to your hardness and household size) and the quality of the control valve are the biggest cost factors, with twin-tank and high-efficiency metered systems at the top of the range.

If well water smells like sulfur, test for hydrogen sulfide and bacteria first. Short-term odors may need shock chlorination; persistent rotten-egg smell usually needs an oxidizing filter sized to your water chemistry.