Public water system record
Estero Mutual
Serves Dillon Beach, Marin County, CA · 206 people served
Federal records show 3 health-based violations and no monitoring/reporting issues for Estero Mutual 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
- 3
- Resolved
- 3
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 0
Key facts
- Estero Mutual draws water from 4 wells and 1 surface water intake (1 of them for emergency, seasonal or other part-time use).
- Highest measured level in the last 10 years: Total Trihalomethanes (TTHMs), 0.098 mg/L, federal limit 0.08 mg/L (1.2 times the limit), 2021.
- Most recent formal enforcement: compliance order (no penalty) by California, March 2022.
- Record on file since 1980, with 26 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 0 unknown out of 142 service lines.
Check whether Estero Mutual 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 0.098 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
220 | Oct 1, 2021 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.095 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
220 | Jul 1, 2021 | Resolved | No |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.081 mg/L, federal limit 0.08 mg/L (at or just above the limit)
|
220 | Oct 1, 2016 | Resolved | No |
Full record since 1980
EPA's records for Estero Mutual go back to 1980. Before October 19, 2016 they list 26 health-based violations (26 resolved) and 28 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1980s | 0 | 26 |
| 1990s | 0 | 1 |
| 2000s | 3 | 1 |
| 2010 to October 18, 2016 | 23 | 0 |
| 2020s | 2 | 0 |
Most recent health-based violation before October 19, 2016: Total Trihalomethanes (TTHMs), began October 2016, Resolved.
Show all 26 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.081 mg/L, federal limit 0.08 mg/L (at or just above the limit)
|
Oct 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.0968 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
Apr 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.103 mg/L, federal limit 0.08 mg/L (1.3 times the limit)
|
Jan 1, 2016 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.13225 mg/L, federal limit 0.08 mg/L (1.7 times the limit)
|
Oct 1, 2015 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.14625 mg/L, federal limit 0.08 mg/L (1.8 times the limit)
|
Jul 1, 2015 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.13225 mg/L, federal limit 0.08 mg/L (1.7 times the limit)
|
Jan 1, 2015 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.0631 mg/L, federal limit 0.06 mg/L (1.1 times the limit)
|
Jan 1, 2015 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.14 mg/L, federal limit 0.08 mg/L (1.8 times the limit)
|
Oct 1, 2014 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1525 mg/L, federal limit 0.08 mg/L (1.9 times the limit)
|
Jul 1, 2014 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1775 mg/L, federal limit 0.08 mg/L (2.2 times the limit)
|
Jan 1, 2014 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1925 mg/L, federal limit 0.08 mg/L (2.4 times the limit)
|
Oct 1, 2013 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 210 µg/L, federal limit 80 µg/L (2.6 times the limit)
|
Jul 1, 2013 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1445 mg/L, federal limit 0.08 mg/L (1.8 times the limit)
|
Jul 1, 2012 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.064825 mg/L, federal limit 0.06 mg/L (1.1 times the limit)
|
Jul 1, 2012 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1245 mg/L, federal limit 0.08 mg/L (1.6 times the limit)
|
Apr 1, 2012 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.065425 mg/L, federal limit 0.06 mg/L (1.1 times the limit)
|
Apr 1, 2012 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1053 mg/L, federal limit 0.08 mg/L (1.3 times the limit)
|
Oct 1, 2011 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.6813 mg/L, federal limit 0.06 mg/L (11 times the limit)
|
Oct 1, 2011 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.077525 mg/L, federal limit 0.06 mg/L (1.3 times the limit)
|
Jul 1, 2011 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.1133 mg/L, federal limit 0.08 mg/L (1.4 times the limit)
|
Jul 1, 2011 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.11075 mg/L, federal limit 0.08 mg/L (1.4 times the limit)
|
Apr 1, 2011 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.11075 mg/L, federal limit 0.08 mg/L (1.4 times the limit)
|
Jan 1, 2011 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.12 mg/L, federal limit 0.08 mg/L (1.5 times the limit)
|
Oct 1, 2010 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Sep 1, 2003 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Dec 1, 2002 | Resolved |
|
Total Coliform (acute)
Contaminant limit exceeded
|
Oct 1, 2000 | Resolved |
Enforcement actions
California regulators took 1 formal enforcement action against Estero Mutual in 2022. The most recent was a compliance order (no penalty) in March 2022.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Mar 18, 2022 | California | Compliance order (no penalty) | 2 violations (2 health-based): Total Trihalomethanes (TTHMs) |
What the violations mean
Total Trihalomethanes (TTHMs)
3 incidentsDisinfection byproduct levels exceeded the federal limit
Long-term TTHM exposure may increase bladder cancer risk
Where the water comes from
Estero Mutual draws water from 4 wells and 1 surface water intake (1 of them for emergency, seasonal or other part-time use).
Annual water quality report
Estero Mutual 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.
Systems serving 500 or fewer people may meet the rule by telling customers the report is available on request, so you may need to ask Estero Mutual for a copy.
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