Xylenes (total)
San Francisco Regional Water System
Xylenes are solvents used in industrial and consumer products, such as cleaning agents and paint thinners. Xylenes cause nervous system damage and may harm developing fetuses.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | ND | 2 | 0 | ND |
| 2015 | ND | 2 | 0 | ND |
| 2016 | ND | 3 | 0 | ND |
| 2017 | ND | 3 | 0 | ND |
| 2018 | ND | 3 | 0 | ND |
| 2019 | ND | 7 | 0 | ND |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 1,800 ppb
The EWG Health Guideline of 1,800 ppb for xylenes 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 harm to the brain and nervous system.
EPA Maximum Contaminant
Level (MCL) 10,000 ppb
The legal limit for xylenes, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1980s. This limit may not fully protect against harm to the brain and nervous system due to xylene exposure.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-06-17 | 9553-016-0904 | ND |
| 2014-06-17 | 9553-001-1130 | ND |
| 2015-05-27 | 9553-001-1235 | ND |
| 2015-06-18 | 9553-015-0915 | ND |
| 2016-06-14 | 9553-001-1105 | ND |
| 2016-06-14 | 9553-015-1231 | ND |
| 2016-06-21 | 9553-016-1055 | ND |
| 2017-06-19 | 9553-015-1100 | ND |
| 2017-06-19 | 9553-016-0953 | ND |
| 2017-06-19 | 9553-001-1025 | ND |
| 2018-06-18 | 9553-016-1100 | ND |
| 2018-06-18 | 9553-001-1032 | ND |
| 2018-06-28 | 9590-015-0950 | ND |
| 2019-06-17 | 9553-001-1012 | ND |
| 2019-06-17 | 9553-015-1119 | ND |
| 2019-06-24 | 9590-034-1035 | ND |
| 2019-06-24 | 9590-035-1137 | ND |
| 2019-06-26 | 9590-031-1430 | ND |
| 2019-06-26 | 9590-032-0925 | ND |
| 2019-06-26 | 9590-033-1125 | ND |