Where It Comes From
Natural organic matter from soils and decaying plants, wastewater/sewage, stormwater runoff, and some industrial discharges [1][2].
How You Are Exposed
Mainly by drinking tap water (especially from surface-water supplies); private wells in peaty or forested areas can also have high TOC [1][2].
Why It Matters
More TOC means more DBPs (such as trihalomethanes and haloacetic acids), which are linked to increased bladder cancer risk and possible reproductive effects. Water systems must control TOC/DBPs under EPA rules [1][2].
Who Is at Risk
People who drink a lot of chlorinated tap water, pregnant people and infants, and users of small systems or private wells with high organic matter [2].
How to Lower Your Exposure
Check your water quality report for TOC/DBPs; use NSF/ANSI 53 or 58 certified filters (activated carbon or reverse osmosis); maintain and, if needed, treat private wells to remove organic matter; contact your utility for options [1][3].
References
- [1]U.S. EPA. Disinfectants and Disinfection Byproducts Rules (Stage 1 & 2). https://www.epa.gov/dwreginfo/disinfection-byproducts-rules
- [2]WHO. Guidelines for Drinking-water Quality, 4th ed. https://www.who.int/publications/i/item/9789241549950
- [3]CDC. Choosing Home Water Filters. https://www.cdc.gov/healthywater/drinking/home/water_filters.html