Note: Just because the latest incident is in 2017 or 2018 doesn't mean your water is free of contaminants! There is a considerable lag between when data is collected and when it is published by the EPA.
| Water System | Type | Measure | Violation | Effects | Begin Date |
|---|---|---|---|---|---|
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| NICASIO VALLEY RANCH MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| NPS GGNRA | Coliform (TCR) | MCL, Acute (TCR) | Maximum Contaminant Level Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2015-09-01 |
| PIEZZI BUILDING | Coliform (TCR) | MCL, Acute (TCR) | Maximum Contaminant Level Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2015-09-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| NICASIO VALLEY RANCH MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| NICASIO VALLEY RANCH MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-01-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2014-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2014-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-07-01 |
| NPS PRNS - GLEN AND WILDCAT CAMPGROUNDS | Coliform (TCR) | MCL, Monthly (TCR) | Maximum Contaminant Level Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2013-06-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-04-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-04-01 |
| BOLINAS COMMUNITY PUD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-10-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-07-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-04-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-04-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-04-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-04-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-10-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-10-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-07-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| ESTERO MUTUAL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| BOLINAS COMMUNITY PUD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-07-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |
| BOLINAS COMMUNITY PUD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-04-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-04-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-01-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-01-01 |
| BOLINAS COMMUNITY PUD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2011-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-01-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-01-01 |
| INVERNESS PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2010-10-01 |
| BOLINAS COMMUNITY PUD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2010-10-01 |
| NICASIO SCHOOL | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2010-10-01 |
| ESTERO MUTUAL | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2010-10-01 |
