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National Drinking Water Database


National Drinking Water Database - Chemical Contaminants

Iodine-131


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

Iodine-131 is a radioactive tracer used in medical applications, and present in the environment due to radioactive fallout from nuclear power station accidents and nuclear weapons testing.

 
Detected
Found above
health guidelines
Found above
legal limit
States
1
-
-
Water utilities
2
-
-
People Served
144,628
-
-

Iodine-131 Exposure by State

Water utilities in 1 states have reported detecting Iodine-131 in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Iodine-131 contamination
SystemsPopulation
Washington2144,628
Total2144,628

The Most Polluted Communities

2 water utilities reported detecting Iodine-131 in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Iodine-131 level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Clark Public Utilities
Vancouver, WA
79,9481 of 1545000 ppb
(545000 ppb)
2City of Kennewick
Kennewick, WA
64,6801 of 3334.44 ppb
(0 to 1003.33 ppb)

Testing Summary for Iodine-131

Are tests routinely required for Iodine-131 by federal law?No
Water suppliers reporting tests for Iodine-131 (2004-2006):3 of 47,576
Average testing rate for water supplier reporting tests (2004-2006):0.6 per year