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National Drinking Water Database

National Drinking Water Database - Chemical Contaminants


Status: Unregulated - EPA has not established a maximum legal limit in tapwater for this contaminant.

Dichloroiodomethane is an unregulated byproduct of tap water disinfection that forms when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.

Found above
health guidelines
Found above
legal limit
Water utilities
People Served

Dichloroiodomethane Exposure by State

Water utilities in 1 states have reported detecting Dichloroiodomethane in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Dichloroiodomethane contamination

The Most Polluted Communities

7 water utilities reported detecting Dichloroiodomethane in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Dichloroiodomethane level

RankSystem Population Served Positive test results of total reported tests Average Level
1River Bend Water Services Inc
Matagorda, TX
1201 of 11.7 ppb
(1.7 ppb)
2Caney Creek Haven Club Water System
Bay City, TX
2881 of 11.5 ppb
(1.5 ppb)
3City of Gladewater
Gladewater, TX
1,8241 of 11.4 ppb
(1.4 ppb)
4Village of Surfside Beach
Freeport, TX
7132 of 21.04 ppb
(0.88 to 1.2 ppb)
5Tbcd Winnie Stowell
Anahuac, TX
5,4451 of 11 ppb
(1 ppb)
6City of Seabrook
Seabrook, TX
2,8501 of 11 ppb
(1 ppb)
7North Central Texas Municipal Water Authority
Munday, TX
9,6661 of 10.6 ppb
(0.6 ppb)

Testing Summary for Dichloroiodomethane

Are tests routinely required for Dichloroiodomethane by federal law?No
Water suppliers reporting tests for Dichloroiodomethane (2004-2007):10 of 47,576
Average testing rate for water supplier reporting tests (2004-2007):0.3 per year