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Contaminant guide

2,3,7,8-TCDD in drinking water

The EPA limit for 2,3,7,8-TCDD in drinking water is 0.000030 µg/L. Of the 4,037 water suppliers tested, 18 had it detected.

0.000030 µg/L
EPA limit (MCL)
0.4%
of suppliers detected it
(18/4,037)

What 2,3,7,8-TCDD is, and why it's regulated

Dioxin (2,3,7,8-TCDD) is a trace by-product of combustion and paper bleaching; it is highly toxic and carcinogenic.

What the EPA limit means

⚖️

0.000030 µg/L

Maximum Contaminant Level — the enforceable ceiling a supplier must stay under.

🎯

0.0 µg/L

Health goal (MCLG) — the level with no known health effect. It is a goal, not a legal limit, and is often zero for carcinogens.

🧪

SYR4

Where these measurements come from. Hover the tag for the EPA programme and years.

Where 2,3,7,8-TCDD was found

The water suppliers reporting the highest levels, worst first. For lead and copper that is the 90th-percentile result the action level is written against; for Six-Year Review data, the 95th percentile of each system's samples.

SupplierCityStateLevel vs EPA limit
Avi Kwa Ame Farms North Needles CA
0.000029 µg/L 97%
of the EPA limit 0.000030 µg/L
Saegertown Borough Saegertown PA
0.000019 µg/L 62%
of the EPA limit 0.000030 µg/L
Caln Mobile Home Park — PA
0.000013 µg/L 43%
of the EPA limit 0.000030 µg/L
Titusville Municipal Water Titusville PA
0.000012 µg/L 40%
of the EPA limit 0.000030 µg/L
Rock Point Community School Bia Rock Point AZ
0.000012 µg/L 39%
of the EPA limit 0.000030 µg/L
Chuska Community Boarding School Bia Tohatchi NM
0.000012 µg/L 39%
of the EPA limit 0.000030 µg/L
Kayenta Community Boarding School Bia Kayenta AZ
0.000011 µg/L 37%
of the EPA limit 0.000030 µg/L
Kinlichee Staff Housing Bia Kinlichee AZ
0.000011 µg/L 36%
of the EPA limit 0.000030 µg/L
Red Rock (Red Valley) Day School Bia Red Valley AZ
0.000011 µg/L 36%
of the EPA limit 0.000030 µg/L
Greasewood Springs Community Boarding School Bia Lower Greasewood AZ
0.000011 µg/L 35%
of the EPA limit 0.000030 µg/L
Crystal Community Boarding School Bia Crystal NM
0.000010 µg/L 35%
of the EPA limit 0.000030 µg/L
Town of Star Valley Water Department Star Valley AZ
0.0000066 µg/L 22%
of the EPA limit 0.000030 µg/L
Beech Fork Water Commission Clay City KY
0.0000050 µg/L 17%
of the EPA limit 0.000030 µg/L
Aqua Pa Superior Ivy Ridge — PA
0.0000050 µg/L 17%
of the EPA limit 0.000030 µg/L
Mountain Water Dist Pikeville KY
0.0000050 µg/L 17%
of the EPA limit 0.000030 µg/L
White Post Mission Ntua White Post Mission, Shonto AZ
0.0000050 µg/L 17%
of the EPA limit 0.000030 µg/L
Tohatchi Public School Tohatchi NM
0.0000035 µg/L 12%
of the EPA limit 0.000030 µg/L
Hamburg Muni Water&Sewer Auth Hamburg PA
0.0000010 µg/L 3.3%
of the EPA limit 0.000030 µg/L

Frequently asked questions about 2,3,7,8-TCDD

What is 2,3,7,8-TCDD in drinking water?

Dioxin (2,3,7,8-TCDD) is a trace by-product of combustion and paper bleaching; it is highly toxic and carcinogenic.

What is the EPA limit for 2,3,7,8-TCDD?

The EPA's Maximum Contaminant Level for 2,3,7,8-TCDD is 0.000030 µg/L, and its health goal (MCLG) is 0.0 µg/L. A result above the limit means the supplier must act; the goal is the level at which no health effects are expected.

How common is 2,3,7,8-TCDD in US tap water?

Of the 4,037 water suppliers with results on file, 18 detected 2,3,7,8-TCDD — 0.4% of those tested.