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National Drinking Water Database


National Drinking Water Database - Chemical Contaminants

Mercury (total inorganic)


Status: Regulated - EPA has established a maximum legal limit in tapwater for this contaminant.

Mercury is a metal from refinery and factory pollution, coal burning, landfill and agricultural runoff and erosion of natural deposits. [read more]

 
Detected
Found above
health guidelines
Found above
legal limit
States
36
14
4
Water utilities
958
29
7
People Served
18,806,824
673,611
20,654

Mercury (total inorganic) Exposure by State

Water utilities in 36 states have reported detecting Mercury (total inorganic) in treated tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies.

StateWater Suppliers with Mercury (total inorganic) contaminationWater suppliers reporting Mercury (total inorganic) above health-based limits
SystemsPopulationSystemsPopulation
Washington2305,2001305,000
Illinois42804,6282171,684
California1916,133,8474124,425
New York49184,657628,936
Missouri2788,850324,107
New Jersey32502,184214,900
Indiana62403,49711,666
South Dakota73,7981876
Maryland211,845,3602674
Wisconsin126912,7951500
North Carolina1068,1622389
Pennsylvania976,2611280
Connecticut1780,069299
Texas101,258,381175
Florida1112,758,75300
Arizona51,244,12200
Utah16666,62000
Minnesota92530,26100
Delaware4220,82000
New Hampshire42175,25900
Ohio1482,39300
Oklahoma779,46200
Massachusetts774,29300
Idaho370,99600
Maine1464,37400
New Mexico938,91900
Alabama638,70300
Iowa229,33700
Kentucky222,24200
Nevada212,15500
South Carolina110,86100
Vermont35,67500
Arkansas15,01200
Montana24,03000
Oregon63,64000
Alaska41,20800
Total95818,806,82429673,611

The Most Polluted Communities

958 water utilities reported detecting Mercury (total inorganic) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Mercury (total inorganic) level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Generac Power Systems Inc
Waukesha, WI
5001 of 21.93 ppb
(0 to 3.86 ppb)
2Clark Rural Water-Kampeska
SD
8761 of 11.8 ppb
(1.8 ppb)
3Town of Clear Spring
Williamsport, MD
4991 of 31.67 ppb
(0 to 5 ppb)
4Country Meadows Comm. Mhp
Frankfort, NY
361 of 11.4 ppb
(1.4 ppb)
5Evergreen Trailer Park - System #1
Clinton, CT
631 of 11.4 ppb
(1.4 ppb)
6Brook Lane Psychiatric Center
Williamsport, MD
1751 of 31.33 ppb
(0 to 4 ppb)
7Alpine Village Mobile H P
Buena Vista Twp, NJ
702 of 21.1 ppb
(1 to 1.2 ppb)
8Sawmill Apts
Rindge, NH
381 of 11.1 ppb
(1.1 ppb)
9Kelso Water Assn
Boring, OR
3501 of 11 ppb
(1 ppb)
10Willow Hills S/D
Fuquay Varina, NC
891 of 21 ppb
(0 to 2 ppb)

Health Based Limits for Mercury (total inorganic)

StandardDescriptionLevel
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.1.2 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.2 ppb
Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.2 ppb
Children's health-based limit for 1-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.2 ppb
Children's health-based limit for 10-day exposureConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.2 ppb
Lifetime health-based limit, non-cancer riskConcentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for a lifetime of exposure. The Lifetime health-based limit (or Health Advisory, HA) is based on exposure for a a 70-kg adult consuming 2 liters of water per day. Source: U.S. Environmental Protection Agency.2 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.10 ppb

Testing Summary for Mercury (total inorganic)

Are tests routinely required for Mercury (total inorganic) by federal law?Yes
Water suppliers reporting tests for Mercury (total inorganic) (2004-2009):29,211 of 47,576
Average testing rate for water supplier reporting tests (2004-2009):0.3 per year

Violation Summary for Mercury (total inorganic)

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards for Mercury (total inorganic) since 2004

Maximum Contaminant Level Exceedance Violations4
Monitoring Violations1,195
Reporting Violations0