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 |
|---|---|---|---|---|---|
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2018-01-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-10-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-07-01 |
| DOMAINE CARNEROS | 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 |
| AMERICAN CANYON, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-04-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-04-01 |
| AMERICAN CANYON, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-04-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2017-01-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2017-01-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2017-01-01 |
| CALISTOGA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-10-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-10-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-10-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-10-01 |
| CALISTOGA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-10-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-10-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-10-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-07-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-07-01 |
| ST. HELENA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2016-07-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-07-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-07-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-04-01 |
| BERRYESSA HIGHLANDS | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| BERRYESSA ESTATES (LBRID) | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| BERRYESSA ESTATES (LBRID) | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| KATHRYN HALL 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 | 2016-01-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2016-01-01 |
| GOOSECROSS CELLARS | 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 | 2016-01-01 |
| FRANK FAMILY 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 | 2015-11-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| CAPELL VALLEY ESTATES | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| CAPELL VALLEY ESTATES | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| PEJU PROVINCE | 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 |
| PEJU PROVINCE | 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 |
| CAPELL VALLEY ESTATES | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-10-01 |
| DARIOUSH 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 | 2015-08-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| ETUDE WINES | 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 | 2015-07-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-07-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-04-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| LINDA FALLS TERRACE MUTUAL | 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 | 2015-01-01 |
| CALISTOGA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| NAPA, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2015-01-01 |
| MILTON ROAD 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 | 2014-12-01 |
| GROTH VINEYARDS & 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 | 2014-10-01 |
| CONN 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 | 2014-10-01 |
| TUCKER ACRES 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 | 2014-07-01 |
| NEWTON VINEYARD | 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 |
| RANCHO LA JOTA | 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 |
| OPUS ONE 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 | 2014-06-01 |
| PINE RIDGE 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 | 2014-06-01 |
| DOMAINE CHANDON | 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 | 2014-05-01 |
| NEWTON VINEYARD | 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 | 2014-04-01 |
| NEWTON VINEYARD | 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 | 2014-04-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2014-03-01 |
| DOMINUS ESTATE 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 | 2013-10-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2013-09-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2013-08-01 |
| NAPA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-07-01 |
| NAPA, CITY OF | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2013-07-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-07-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2013-07-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-07-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-04-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-04-01 |
| AMERICAN CANYON, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-01-01 |
| AMERICAN CANYON, CITY OF | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2013-01-01 |
| ROUND HILL 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 | 2013-01-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2012-10-01 |
| BERRYESSA ESTATES (LBRID) | 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 |
| MILTON ROAD 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 | 2012-08-01 |
| MEYERS WATER CO. | 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 | 2012-07-01 |
| BERRYESSA ESTATES (LBRID) | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-07-01 |
| BERRYESSA ESTATES (LBRID) | TTHM | MCL, Average | Maximum Contaminant Level Violation | Liver, kidney or central nervous system problems; increased risk of cancer | 2012-07-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2012-03-01 |
| HOWELL MTN SCHOOL | 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 | 2012-02-01 |
| NAPA COUNTY SCHOOLS: POPE VALLEY | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-01-01 |
| NAPA COUNTY SCHOOLS: POPE VALLEY | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2012-01-01 |
| MUMM OF NAPA VALLEY | Coliform (TCR) | Notification, State | Other Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2011-11-01 |
| MUMM OF NAPA VALLEY | Coliform (TCR) | Notification, State | Other Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2011-11-01 |
| VAILIMA ESTATES MUTUAL WATER | 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 | 2011-11-01 |
| NAPA VALLEY MARINA | 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 |
| NVUSD: CARNEROS SCHOOL | 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 | 2011-10-01 |
| SKYLINE PARK | Coliform (TCR) | Notification, State | Other Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2011-07-01 |
| SKYLINE PARK | Coliform (TCR) | Notification, State | Other Violation | Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 | 2011-07-01 |
| HOWELL MOUNTAIN MUTUAL WATER COMPANY | Total Haloacetic Acids (HAA5) | MCL, Average | Maximum Contaminant Level Violation | Increased risk of cancer | 2011-04-01 |