Oak Knolls Mutual Water Company
Published drinking-water records and contacts for Oak Knolls Mutual Water Company. System CA1500465. Review sources and dates; not a real-time water assessment.
- System ID
- CA1500465
- State or territory
- CA
- Published population served
- 123
- System type (source code)
- CWS
Published records and dates
- Lead and copper monitoring summaries: 13 — 1996-01-01 – 2025-12-31
- California DDW laboratory results: 18 — 2026-01-26 – 2026-06-24
Missing records here do not mean the provider did not test. Published records are not a real-time assessment of your tap water.
Published testing results
Selected recent records are shown below. Different sampling locations and dates are not interchangeable. These excerpts are not a complete testing history.
“<” means below the stated reporting limit, not zero. A reported measurement alone is not a safety verdict. Read an example
Lead and copper: 90th-percentile summaries
These describe a monitoring period across sampled locations, not the result at your home. How to read the 90th percentile
| Substance | Published 90th percentile | Monitoring period | Source quarter |
|---|---|---|---|
| Lead (PB90) | 0.0009 mg/L | 2023-01-01 – 2025-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2020-01-01 – 2022-12-31 | 2026Q3 |
| Lead (PB90) | 0.007 mg/L | 2019-01-01 – 2019-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2018-01-01 – 2018-12-31 | 2026Q3 |
| Lead (PB90) | 0.003 mg/L | 2017-07-01 – 2017-12-31 | 2026Q3 |
| Lead (PB90) | 0.002 mg/L | 2017-01-01 – 2017-06-30 | 2026Q3 |
| Lead (PB90) | 0.02 mg/L | 2016-07-01 – 2016-12-31 | 2026Q3 |
| Lead (PB90) | 0.078 mg/L | 2016-01-01 – 2016-06-30 | 2026Q3 |
| Substance | Published result | Sample date | Location / source |
|---|---|---|---|
| NITRATE | 11 MG/L | 2026-06-24 | WELL 02 / California DDW laboratory results |
| NITRATE | 12 MG/L | 2026-06-24 | WELL 01 / California DDW laboratory results |
| NITRATE | 8.0 MG/L | 2026-06-24 | WELL 03 / California DDW laboratory results |
| NITRATE | 9.0 MG/L | 2026-05-20 | WELL 03 / California DDW laboratory results |
| NITRATE | 11 MG/L | 2026-05-20 | WELL 02 / California DDW laboratory results |
| NITRATE | 13 MG/L | 2026-05-20 | WELL 01 / California DDW laboratory results |
| NITRATE | 8.4 MG/L | 2026-04-20 | WELL 03 / California DDW laboratory results |
| NITRATE | 14 MG/L | 2026-04-20 | WELL 01 / California DDW laboratory results |
| NITRATE | 11 MG/L | 2026-04-20 | WELL 02 / California DDW laboratory results |
| NITRATE | 14 MG/L | 2026-03-25 | WELL 01 / California DDW laboratory results |
| NITRATE | 10 MG/L | 2026-03-25 | WELL 02 / California DDW laboratory results |
| NITRATE | 9.5 MG/L | 2026-03-25 | WELL 03 / California DDW laboratory results |
State sampling points can include untreated water. Publisher qualifiers and units are retained; consult the full source notes before interpreting a record.
Download state records with source notes (CSV)
Published compliance history
17 imported records. Status is as recorded in the source; historical records are not current advisories. Missing records do not establish that no violations occurred.
| Rule / record | Period | Recorded status | Health-based (EPA classification) | Source quarter |
|---|---|---|---|---|
| Nitrate Rule / Maximum Contaminant Level Violation, Single Sample | 2025-01-01 – 2025-03-31 | Resolved | Yes | 2026Q3 |
| Lead and Copper Rule Revisions / LSL Inventory | 2024-10-17 – — | Unaddressed | Yes | 2026Q3 |
| Lead and Copper Rule Revisions / LSL Reporting | 2024-10-17 – — | Unaddressed | No | 2026Q3 |
| Nitrate Rule / Maximum Contaminant Level Violation, Single Sample | 2024-10-01 – 2024-12-31 | Resolved | Yes | 2026Q3 |
| Nitrate Rule / Maximum Contaminant Level Violation, Single Sample | 2024-07-01 – 2024-09-30 | Resolved | Yes | 2026Q3 |
| Nitrate Rule / Maximum Contaminant Level Violation, Single Sample | 2024-04-01 – 2024-06-30 | Archived | Yes | 2026Q3 |
| Nitrate Rule / Maximum Contaminant Level Violation, Single Sample | 2024-01-01 – 2024-03-31 | Archived | Yes | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-09-01 – 1984-09-30 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-08-01 – 1984-08-31 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-07-01 – 1984-07-31 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-06-01 – 1984-06-30 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-05-01 – 1984-05-31 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-03-01 – 1984-03-31 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1984-02-01 – 1984-02-29 | Archived | No | 2026Q3 |
| Miscellaneous Other Rules / Notification, Public | 1983-10-01 – 1983-10-31 | Archived | No | 2026Q3 |
| Radionuclides and Revised Rad Rule / Monitoring, Regular | 1981-10-01 – 1982-09-30 | Archived | No | 2026Q3 |
| Radionuclides and Revised Rad Rule / Monitoring, Regular | 1980-10-30 – 1981-10-29 | Archived | No | 2026Q3 |
Source dates and refresh checks
A refresh check is not a sample date. Publication periods, sample dates and checks are shown separately.
- EPA SDWIS lead/copper summaries and service areas — source period: — – —; last checked: 2026-10-17
- EPA SDWIS contacts and compliance records — source period: — – —; last checked: 2026-10-17
- EPA UCMR 5 sample results — source period: 2023-01-03 – 2026-06-17; last checked: 2026-10-17
- California DDW laboratory results — last successful check: 2026-10-17
Administrative contact (EPA filing)
Hanna, Wesley: 760-223-1664
An administrative filing contact may not be a customer-service line. Confirm current contact details with the provider.