Activated Carbon Filtration
A water treatment method using porous carbon material to adsorb contaminants — effective for removing chlorine, many organic chemicals, some PFAS, and improving taste and odor.
How It Works
Activated carbon filtration works by adsorption: contaminants stick to the enormous surface area of the carbon (1 gram of activated carbon has the surface area of a tennis court). Granular activated carbon (GAC) filters are used at the treatment plant level for removing PFAS, volatile organic compounds (VOCs), pesticides, and disinfection byproduct precursors. Point-of-use carbon filters (Brita, PUR, refrigerator filters) are effective for chlorine taste/odor, some lead, and certain organic contaminants but have limited effectiveness against PFAS, nitrate, fluoride, and most heavy metals. Carbon filters must be replaced regularly — a saturated filter stops working and can even release previously captured contaminants.
Related Terms
- PFAS (Forever Chemicals) — Per- and polyfluoroalkyl substances — a class of thousands of synthetic chemicals that don't break down in the environment, accumulate in the human body, and are linked to cancer, immune disorders, and developmental problems.
- Reverse Osmosis (RO) — A water treatment process that forces water through a semipermeable membrane to remove up to 99% of contaminants — including lead, PFAS, nitrate, arsenic, and most other dissolved substances.
- Chlorination — The most common method of disinfecting drinking water — adding chlorine or chloramine to kill bacteria, viruses, and parasites before water reaches your tap.
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About This Definition
This definition is part of the IsWaterSafe Drinking Water Safety Glossary — 22 terms explaining water contaminants, treatment methods, and safety standards. Written for homeowners, renters, journalists, and public health professionals.