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 |
|---|---|---|---|---|---|
| CSP-FORT ROSS STATE PARK | 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 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-07-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2018-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2018-07-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-04-01 |
| CSP-FORT ROSS STATE PARK | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2018-04-01 |
| SONOMA COUNTY CSA 41-JENNER | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2018-01-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2018-01-01 |
| CSP-FORT ROSS STATE PARK | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2018-01-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2018-01-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2018-01-01 |
| CSP-FORT ROSS STATE PARK | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-10-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-10-01 |
| SONOMA COUNTY CSA 41-JENNER | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-10-01 |
| DELORES LANE WATER SYSTEM | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-10-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-10-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2017-10-01 |
| DELORES LANE WATER SYSTEM | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-10-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2017-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2017-07-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-07-01 |
| CSP-FORT ROSS STATE PARK | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2017-04-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-04-01 |
| CSP-FORT ROSS STATE PARK | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-04-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-04-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2017-04-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-01-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2017-01-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-10-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-10-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-07-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-07-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-07-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-07-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2016-04-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2016-04-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-04-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-04-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-04-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-04-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-04-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-04-01 |
| DUNCANS MILLS CAMPING CLUB | 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 |
| TRUETT & HURST WINERY | 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 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-01-01 |
| TIMBER COVE COUNTY WATER DISTRICT | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| TIMBER COVE COUNTY WATER DISTRICT | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2016-01-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2016-01-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-01-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2016-01-01 |
| VALLEY FORD HOTEL | Nitrate | MCL, Single Sample | Maximum Contaminant Level Violation | Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. | 2016-01-01 |
| MARK WEST NEIGHBORHOOD CHURCH | 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 | 2015-12-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-10-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-10-01 |
| BODEGA WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| SONOMA DEVELOPMENTAL CENTER | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-10-01 |
| STONESTREET WINERY | 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 | 2015-10-01 |
| MANZANA PRODUCTS COMPANY, INC. | 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 | 2015-10-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-10-01 |
| SONOMA COUNTY CSA 41-FREESTONE | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-10-01 |
| SONOMA COUNTY CSA 41-FREESTONE | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-10-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-10-01 |
| BODEGA WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-10-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | 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 | 2015-09-01 |
| LIETO WATER SYSTEM (REACH CHARTR SCHOOL) | 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 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-07-01 |
| SONOMA COUNTY CSA 41-FREESTONE | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-07-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-07-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-07-01 |
| BODEGA WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| TLC CHILD & FAMILY SERVICES | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-07-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-07-01 |
| BODEGA WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| BODEGA WATER COMPANY | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-07-01 |
| BODEGA WATER COMPANY | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-07-01 |
| SONOMA COUNTY CSA 41-FREESTONE | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2015-07-01 |
| EKTIMO VINEYARDS | 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 | 2015-05-01 |
| LELAND FLY FISHING OUTFITTERS | 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 | 2015-05-01 |
| MADRONE MUTUAL WATER COMPANY | 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 | 2015-05-01 |
| EKTIMO VINEYARDS | 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 | 2015-05-01 |
| MATANZAS CREEK WINERY | 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 | 2015-04-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-04-01 |
| SAINT ANNE'S CROSSING WINERY | 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 | 2015-04-01 |
| PEDRONCELLI WINERY | 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 | 2015-04-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-04-01 |
| LOCH HAVEN MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-04-01 |
| EL PORTAL MOBILE ESTATES | Trichloroethylene | MCL, Average | Maximum Contaminant Level Violation | Liver problems; increased risk of cancer | 2015-04-01 |
| EKTIMO VINEYARDS | 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 | 2015-03-01 |
| EKTIMO VINEYARDS | 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 | 2015-03-01 |
| WASHOE HOUSE | 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 | 2015-02-01 |
| MADRONE MUTUAL WATER COMPANY | 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 | 2015-02-01 |
| MADRONE MUTUAL WATER COMPANY | 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 | 2015-02-01 |
| LOMBARDI'S DELI & BBQ | 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 | 2015-02-01 |
| LOMBARDI'S DELI & BBQ | 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 | 2015-02-01 |
| MOUNT WESKE ESTATES MUTUAL WATER COMPANY | Arsenic | MCL, Average | Maximum Contaminant Level Violation | Skin damage or problems with circulatory systems, and may have increased risk of getting cancer | 2015-01-01 |