The Power of Information

National Drinking Water Database


Total trihalomethanes (TTHMs) in Virginia


Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform. [read more]

The Most Polluted Communities in Virginia

794 water utilities reported detecting Total trihalomethanes (TTHMs) in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Total trihalomethanes (TTHMs) level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Martin Creek
Salem, VA
4951 of 1200 ppb
(200 ppb)
2Delaney Court
Salem, VA
2241 of 1200 ppb
(200 ppb)
3Lake Caroline Wtp
Ruther Glen, VA
3,37016 of 16152.56 ppb
(15 to 230 ppb)
4Town of Alberta
Alberta, VA
80016 of 16129.04 ppb
(58 to 231 ppb)
5Riverdale
Halifax, VA
30010 of 10106.58 ppb
(31 to 175 ppb)
6Town of LA Crosse
La Crosse, VA
75017 of 17100.01 ppb
(53 to 181 ppb)
7Gwynns Island Condo
Deltaville, VA
508 of 898 ppb
(26 to 194 ppb)
8Town of Brodnax
Brodnax, VA
31715 of 1597.17 ppb
(55 to 164 ppb)
9Town of Boydton
Boydton, VA
56316 of 1682.49 ppb
(46 to 121 ppb)
10Town of Blackstone
Blackstone, VA
3,87035 of 3582.33 ppb
(25 to 163 ppb)

Health Based Limits for Total trihalomethanes (TTHMs)

StandardDescriptionLevel
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.9.8 ppb
EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.11.5 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.80 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.130 ppb
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.980 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.1835 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.4860 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.10600 ppb

Violation Summary for Total trihalomethanes (TTHMs) in Virginia

Data from the U.S. Environmental Protection Agency includes the following violations of federal standards in Virginia since 2004

Violation TypeNumber of Violations
Monitoring and Reporting Disinfection Byproduct Rule121
Over maximum contaminant level, Average97