Public water system record
Berryessa Highlands
Serves an area of Napa County, CA · 715 people served
Federal records show 15 health-based violations and 3 monitoring/reporting issues for Berryessa Highlands in the last ten years. The most serious issue in this window was a resolved Total Trihalomethanes (TTHMs) violation.
System profile
- Health-based violations, last 10 years
- 15
- Resolved
- 15
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 3
Key facts
- Berryessa Highlands draws water from 1 surface water intake.
- Highest measured level in the last 10 years: Total Trihalomethanes (TTHMs), 0.1 mg/L, federal limit 0.08 mg/L (1.3 times the limit), 2018.
- Most recent formal enforcement: compliance order (no penalty) by California, October 2024.
- Record on file since 1993, with 6 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 0 unknown out of 240 service lines.
Check whether Berryessa Highlands serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
| Contaminant | Rule family | Start date | Status | Acute |
|---|---|---|---|---|
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.0823 mg/L, federal limit 0.08 mg/L (at or just above the limit)
|
220 | Apr 1, 2020 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.0863 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Jan 1, 2020 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.087 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Oct 1, 2019 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.0845 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Jul 1, 2019 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.091 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Apr 1, 2019 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 89.8 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
220 | Jan 1, 2019 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.09 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Oct 1, 2018 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 91.8 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
220 | Jul 1, 2018 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 84.3 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
220 | Apr 1, 2018 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1 mg/L, federal limit 0.08 mg/L (1.3 times the limit)
|
220 | Jan 1, 2018 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.096 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
220 | Oct 1, 2017 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.097 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
220 | Jul 1, 2017 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.099 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
220 | Apr 1, 2017 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.08675 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Jan 1, 2017 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.091 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
220 | Oct 1, 2016 | Resolved | No |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
Revised Total Coliform Rule
Monitoring violation
|
Aug 1, 2024 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
|
Revised Total Coliform Rule
Monitoring violation
|
Dec 1, 2020 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
|
Public Notice
OTHER
|
Feb 1, 2014 | Resolved |
Full record since 1993
EPA's records for Berryessa Highlands go back to 1993. Before October 19, 2016 they list 6 health-based violations (6 resolved) and 6 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1990s | 0 | 2 |
| 2000s | 0 | 1 |
| 2010 to October 18, 2016 | 6 | 3 |
| October 19, 2016 to 2019 | 12 | 0 |
| 2020s | 2 | 2 |
Most recent health-based violation before October 19, 2016: Total Trihalomethanes (TTHMs), began October 2016, Resolved.
Show all 6 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.091 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
Oct 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 89.25 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
Jul 1, 2016 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 61.6 µg/L, federal limit 60 µg/L (at or just above the limit)
|
Apr 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 89 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
Apr 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 89 µg/L, federal limit 80 µg/L (1.1 times the limit)
|
Jan 1, 2016 | Resolved |
|
Surface Water Treatment Rule
Treatment technique failure
|
Jan 1, 2014 | Resolved |
Enforcement actions
California regulators took 10 formal enforcement actions against Berryessa Highlands between 1998 and 2024. The most recent was a compliance order (no penalty) in October 2024.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Oct 1, 2024 | California | Compliance order (no penalty) | 1 violation: Revised Total Coliform Rule |
| Feb 8, 2021 | California | Compliance order (no penalty) | 1 violation: Revised Total Coliform Rule |
| Jul 27, 2020 | California | Compliance order (no penalty) | 3 violations (3 health-based): Total Trihalomethanes (TTHMs) |
| Jul 16, 2019 | California | Compliance order (no penalty) | 7 violations (7 health-based): Total Trihalomethanes (TTHMs) |
| Nov 19, 2018 | California | Compliance order (no penalty) | 5 violations (5 health-based): Total Trihalomethanes (TTHMs) |
| Jun 30, 2016 | California | Compliance order (no penalty) | 10 violations (10 health-based): Total Trihalomethanes (TTHMs), Haloacetic Acids (HAA5) |
| Jun 17, 2014 | California | Compliance order (no penalty) | 2 violations: Haloacetic Acids (HAA5), Total Trihalomethanes (TTHMs) |
| May 21, 2014 | California | Compliance order (no penalty) | 2 violations (1 health-based): Public Notice, Surface Water Treatment Rule |
| Feb 27, 2001 | California | Compliance order (no penalty) | 1 violation: Total Coliform |
| Nov 27, 1998 | California | Compliance order (no penalty) | 1 violation: Surface Water Treatment Rule |
What the violations mean
Total Trihalomethanes (TTHMs)
15 incidentsDisinfection byproduct levels exceeded the federal limit
Long-term TTHM exposure may increase bladder cancer risk
Where the water comes from
Berryessa Highlands draws water from 1 surface water intake.
Annual water quality report
Berryessa Highlands must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Where the state allows it, systems serving fewer than 10,000 people may publish the report in a local newspaper or news site instead of mailing it, and must provide a copy on request.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by California.
Certified drinking water labs by state EPA guidance for private wells