The Power of Information

National Drinking Water Database

MTBE in Delaware

MTBE (methyl tert-butyl ether) is a fuel additive that had been used as an octane enhancer in unleaded gasoline; it contaminates groundwater due to spillage or leakage at gas stations, and has been banned or scheduled for phaseout in most states.

The Most Polluted Communities in Delaware

25 water utilities reported detecting MTBE in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average MTBE level

RankSystem Population Served Positive test results of total reported tests Average Level
1Pepper Ridge Park
18010 of 106.34 ppb
(0.79 to 40.8 ppb)
2Villas of Grandview
Wilmington, DE
10710 of 134.18 ppb
(0 to 16.2 ppb)
3Selbyville Water Department
Selbyville, DE
1,64525 of 272.97 ppb
(0 to 13.2 ppb)
4Avalon Woods Owners Assoc Inc
Georgetown, DE
3069 of 122.08 ppb
(0 to 6.48 ppb)
5County Seat Gardens
Georgetown, DE
2971 of 12.06 ppb
(2.06 ppb)
6Laurel Village Mobile Home Park
Lewes, DE
9184 of 60.95 ppb
(0 to 2.06 ppb)
7Smyrna Water Department
Smyrna, DE
10,00110 of 120.95 ppb
(0 to 4.22 ppb)
8Wild Quail District
Dover, DE
79214 of 180.88 ppb
(0 to 3.55 ppb)
9Rehoboth Bay Community
Rehoboth, DE
6259 of 150.87 ppb
(0 to 4.51 ppb)
10Shady Oak Trailer Court
Georgetown, DE
1081 of 20.59 ppb
(0 to 1.17 ppb)

Health Based Limits for MTBE

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.13 ppb

Violation Summary for MTBE in Delaware

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

Violation TypeNumber of Violations
Over maximum contaminant level, Average3