Chromium (total)
California Water Service Company Oak Hills
Chromium is a naturally occurring metal, but industrial uses can elevate its levels in water. One form, hexavalent chromium, causes cancer. Total chromium is not a good indicator of the amount of hexavalent chromium in drinking water.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 10.1 ppb | 6 | 4 | ND - 17.8 ppb |
| 2019 | 10.5 ppb | 2 | 2 | 10.00 ppb - 11.0 ppb |
| 2020 | N/A | 0 | 0 | N/A |
| 2021 | 16.0 ppb | 1 | 1 | 16.0 ppb |
| 2022 | 11.0 ppb | 2 | 2 | 10.00 ppb - 12.0 ppb |
| 2023 | N/A | 0 | 0 | N/A |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EPA Maximum Contaminant
Level (MCL): 100 ppb
The legal limit for total chromium, established in 1991, was based on a 1958 toxicity study in laboratory animals, and applies to both the less-toxic trivalent chromium and the more-toxic hexavalent chromium forms of this compound. This limit does not protect against the risk of cancer from ingestion of hexavalent chromium.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-10-16 | CA2710019_003_003-201810161030 | 17.8 ppb |
| 2018-10-16 | CA2710019_010_010-201810161033 | 11.5 ppb |
| 2018-10-22 | CA2710019_003_003-201810220949 | 15.9 ppb |
| 2018-10-22 | CA2710019_010_010-201810220946 | ND |
| 2018-10-29 | CA2710019_003_003-201810291142 | 15.4 ppb |
| 2018-10-29 | CA2710019_010_010-201810291139 | ND |
| 2019-06-19 | CA2710019_008_008-201906191328 | 10.00 ppb |
| 2019-09-12 | CA2710019_003_003-201909121359 | 11.0 ppb |
| 2021-06-29 | CA2710019_001_001-202106291345 | 16.0 ppb |
| 2022-06-22 | CA2710019_008_008-202206221336 | 12.0 ppb |
| 2022-09-22 | CA2710019_003_003-202209221415 | 10.00 ppb |