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 |
|---|---|---|---|---|---|
| CDCR - SIERRA CONSERVATION CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-07-01 |
| RUSH CREEK LODGE WATER SYSTEM | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2018-07-01 |
| CDCR - SIERRA CONSERVATION CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-04-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| BLUEBELL VALLEY MWC | 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 | 2016-03-01 |
| BLUEBELL VALLEY MWC | 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 | 2016-03-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| CASCADE ESTATES | 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 | 2015-10-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| CASCADE ESTATES | 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 | 2015-10-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| BLUEBELL VALLEY MWC | 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 | 2015-02-01 |
| BLUEBELL VALLEY MWC | 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 | 2015-02-01 |
| SONORA MEADOWS MUTUAL WTR CO | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-01-01 |
| SONORA MEADOWS MUTUAL WTR CO | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-01-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-10-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-10-01 |
| USFS SOURGRASS CAMPGD | 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 | 2014-09-01 |
| USFS SOURGRASS CAMPGD | 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 | 2014-09-01 |
| SILVER SPUR CHRISTIAN CAMP | 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 | 2014-08-01 |
| SILVER SPUR CHRISTIAN CAMP | 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 | 2014-08-01 |
| USFS SOURGRASS CAMPGD | 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 | 2014-07-01 |
| USFS SOURGRASS CAMPGD | 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 | 2014-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-07-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-04-01 |
| USFS PINECREST REC AREA | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2014-04-01 |
| SPICER MEADOW CAMPGROUND | 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 | 2012-09-01 |
| SPICER MEADOW CAMPGROUND | 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 | 2012-09-01 |
| SIERRA VILLAGE MUTUAL WATER CO | 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 | 2012-05-01 |
| SIERRA VILLAGE MUTUAL WATER CO | 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 | 2012-05-01 |
| USFS - GROVELAND RANGER STN. | 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 | 2011-10-01 |
| USFS CHERRY VALLEY CAMPGD | 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 | 2011-09-01 |
| CHRISTIAN HEIGHTS ASEMBLY OF GOD | 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 | 2011-02-01 |
| USFS - GROVELAND RANGER STN. | 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 | 2010-11-01 |
| RED BARN | 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 | 2010-10-01 |
| HOUSEBOAT MINI MART | 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 | 2010-07-01 |
| YOSEMITE NPS-HODGDON MEADOW | COPPER, FREE | MPL Non-Compliance | Treatment Technique Violation | Short term exposure: Gastrointestinal distress | 2009-07-01 |
| YOSEMITE NPS-HODGDON MEADOW | COPPER, FREE | MPL Non-Compliance | Treatment Technique Violation | Short term exposure: Gastrointestinal distress | 2009-07-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2009-04-01 |
| DEL ORO WATER COMPANY - STRAWBERRY DIV. | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2009-01-01 |
| YOSEMITE NPS-HODGDON MEADOW | COPPER, FREE | MPL Non-Compliance | Treatment Technique Violation | Short term exposure: Gastrointestinal distress | 2009-01-01 |
| DEL ORO WATER COMPANY - STRAWBERRY DIV. | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2009-01-01 |
| YOSEMITE NPS-HODGDON MEADOW | COPPER, FREE | MPL Non-Compliance | Treatment Technique Violation | Short term exposure: Gastrointestinal distress | 2009-01-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2008-10-01 |
| LAKE DON PEDRO CSD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2007-07-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2007-07-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2007-04-01 |
| LAKE DON PEDRO CSD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2007-04-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2007-01-01 |
| LAKE DON PEDRO CSD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2007-01-01 |
| LAKE DON PEDRO CSD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2006-10-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2006-10-01 |
| LAKE DON PEDRO CSD | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2006-01-01 |
| LAKE DON PEDRO CSD | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2006-01-01 |
| LAKE DON PEDRO CSD | TTHM | Notification, State | Other Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2005-01-01 |