1,4-Dioxane in drinking water
An industrial solvent stabilizer that moves fast in groundwater. Notable on Long Island and around old solvent sites.
Health: EPA classifies it as likely carcinogenic. 0.35 ppb corresponds to a 1-in-a-million lifetime cancer risk.
Across the US
Those 334 systems serve about 32.4 million people.
From EPA's earlier unregulated contaminant testing (UCMR 3). These results are older, so ask your utility for current data.
Highest results
| Water system | People | Highest result |
|---|---|---|
| Hicksville Water District | 48,000 | 34 ppb |
| Rockford Water System | 147,051 | 22.9 ppb |
| City of Sanford | 48,350 | 13.3 ppb |
| Moore County Public Utilities – Pinehurst | 31,390 | 12 ppb |
| Water Authority of Western Nassau | 120,000 | 10 ppb |
| Town of Hempstead Water Department | 110,000 | 10 ppb |
| Fayetteville Public Works Commission | 226,441 | 8.8 ppb |
| Bethpage Water District | 33,000 | 8.5 ppb |
| California Water Service – East Los Angeles | 142,140 | 7.8 ppb |
| Tract 180 Mutual Water Company | 14,000 | 7.6 ppb |
| City of Tucson | 732,906 | 6.7 ppb |
| Bellflower – Somerset Mutual Water Company | 46,300 | 6.3 ppb |
| Beaver Falls Municipal Authority | 49,500 | 6.2 ppb |
| Golden State Water Company – Bell, Bell Gardens | 55,050 | 6 ppb |
| City of Lynwood Water Dept. | 66,967 | 5.9 ppb |
| Golden State Water Company – Norwalk | 43,167 | 5.9 ppb |
| New Jersey American Water – Washington/Oxford | 10,719 | 5.83 ppb |
| Plainview Water District | 34,000 | 5.8 ppb |
| Town of Holly Springs | 51,947 | 5.6 ppb |
| Merchantville Pennsauken Water System | 47,144 | 5.6 ppb |
| Town of Fuquay-Varina | 42,954 | 5.6 ppb |
| New Brighton Water System | 22,902 | 5.5 ppb |
| Mesa Water District | 110,000 | 5.42 ppb |
| Aqua NJ – Eastern Division | 12,200 | 5.4 ppb |
| Old North Utilities Services/Ft Bragg | 65,000 | 4.9 ppb |
States with the most detections
- California: 151
- New Jersey: 80
- Illinois: 61
- Pennsylvania: 59
- Alabama: 49
- Massachusetts: 49
- New York: 48
- Ohio: 48
- North Carolina: 45
- Florida: 45
- South Carolina: 42
- Texas: 42
Sources
The limits, health goals and health effects on this page come from these EPA sources. The results come from EPA's monitoring data for each water system.
- EPA: UCMR occurrence data (the test results)
- EPA: National Primary Drinking Water Regulations (limits and health effects table)
This page summarizes public regulatory information. It is not medical advice. How we source and check this site.
Questions
What is the safe level of 1,4-Dioxane in drinking water?
There is no federal legal limit. EPA cancer risk level (1 in a million): 0.35 ppb.
How do I remove 1,4-Dioxane from tap water?
See the filter guidance on this page: look for a product certified for 1,4-Dioxane specifically, and check the claim in NSF's certified product listings.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.