MTBE
Deforest Waterworks
MTBE was used as gasoline oxygenation additive to boost the octane number. In 2005, MTBE was replaced by ethanol as a gasoline additive. MTBE causes cancers in rats.
23
Samples
0
Samples exceeding legal limit (MCL)
2
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 11.0 ppb | 2 | 2 | 7.00 ppb - 15.0 ppb |
| 2019 | 5.95 ppb | 2 | 2 | 4.60 ppb - 7.30 ppb |
| 2020 | 4.15 ppb | 2 | 2 | 2.80 ppb - 5.50 ppb |
| 2021 | 8.45 ppb | 2 | 2 | 3.90 ppb - 13.0 ppb |
| 2022 | 9.27 ppb | 3 | 3 | 7.40 ppb - 11.0 ppb |
| 2023 | 3.66 ppb | 12 | 5 | ND - 14.0 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 13 ppb
The EWG Health Guideline of 13 ppb for MTBE was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-03-13 | 1044929 | 7.00 ppb |
| 2018-08-29 | 404007001 | 15.0 ppb |
| 2019-06-19 | 1129331 | 4.60 ppb |
| 2019-09-10 | 1146800 | 7.30 ppb |
| 2020-06-02 | 1191107 | 2.80 ppb |
| 2020-08-31 | 1210974 | 5.50 ppb |
| 2021-04-13 | 1248611 | 13.0 ppb |
| 2021-08-25 | 1273964 | 3.90 ppb |
| 2022-07-26 | 1326226 | 9.40 ppb |
| 2022-08-23 | 1331556 | 7.40 ppb |
| 2022-08-23 | 1331555 | 11.0 ppb |
| 2023-03-21 | 669282001 | ND |
| 2023-03-21 | 669283001 | 11.0 ppb |
| 2023-06-08 | 682743001 | ND |
| 2023-06-08 | 682745001 | 5.90 ppb |
| 2023-07-25 | 691015001 | ND |
| 2023-07-25 | 691015002 | ND |
| 2023-09-07 | 698953003 | ND |
| 2023-09-07 | 698953001 | 14.0 ppb |
| 2023-09-19 | 701205001 | ND |
| 2023-09-19 | 701208001 | 8.20 ppb |
| 2023-12-12 | 714406002 | ND |
| 2023-12-12 | 714406001 | 4.80 ppb |