Chromium (hexavalent)
Castle Rock
Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).
20
Samples
0
Samples exceeding legal limit (MCL)
16
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.251 ppb | 10 | 7 | ND - 0.760 ppb |
| 2015 | 0.257 ppb | 10 | 9 | ND - 0.920 ppb |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.02 ppb
The EWG Health Guideline of 0.02 ppb for chromium (hexavalent) 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 | Result |
|---|---|
| 2014-08-13 | ND |
| 2014-08-13 | 0.600 ppb |
| 2014-08-14 | ND |
| 2014-08-14 | 0.1000 ppb |
| 2014-08-14 | 0.0310 ppb |
| 2014-08-14 | ND |
| 2014-09-02 | 0.760 ppb |
| 2014-09-02 | 0.280 ppb |
| 2014-11-19 | 0.580 ppb |
| 2014-11-19 | 0.160 ppb |
| 2015-02-11 | 0.520 ppb |
| 2015-02-11 | 0.0370 ppb |
| 2015-02-11 | 0.160 ppb |
| 2015-02-11 | 0.400 ppb |
| 2015-05-19 | 0.300 ppb |
| 2015-05-19 | 0.920 ppb |
| 2015-08-18 | 0.0300 ppb |
| 2015-08-18 | ND |
| 2015-08-18 | 0.150 ppb |
| 2015-08-18 | 0.0500 ppb |