City of Sonoma
Published drinking-water records and contacts for City of Sonoma. System CA4910012. Review sources and dates; not a real-time water assessment.
- System ID
- CA4910012
- State or territory
- CA
- Published population served
- 11725
- System type (source code)
- CWS
Published records and dates
- PFAS / lithium (EPA UCMR 5): 360 — 2023-07-19 – 2024-01-16
- Lead and copper monitoring summaries: 33 — 1992-01-01 – 2023-12-31
- California DDW laboratory results: 495 — 2026-01-14 – 2026-06-09
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
| Substance | Published result | Reporting limit | Sample date | Sampling location |
|---|---|---|---|---|
| 11Cl-PF3OUdS | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| 4:2 FTS | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 4 TP / 4910012805 |
| 6:2 FTS | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Well 4 TP / 4910012805 |
| 8:2 FTS | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| 9Cl-PF3ONS | < 0.002 µg/L | 0.002 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| ADONA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 1 TP / 4910012807 |
| HFPO-DA | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Well 2 TP / 4910012806 |
| NEtFOSAA | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Well 8 / 4910012808 |
| NFDHA | < 0.02 µg/L | 0.02 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| NMeFOSAA | < 0.006 µg/L | 0.006 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| PFBA | < 0.005 µg/L | 0.005 µg/L | 2024-01-16 | Well 1 TP / 4910012807 |
| PFBS | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 4 TP / 4910012805 |
| PFDA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 2 TP / 4910012806 |
| PFDoA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 2 TP / 4910012806 |
| PFEESA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
| PFHpA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 4 TP / 4910012805 |
| PFHpS | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 1 TP / 4910012807 |
| PFHxA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
| PFHxS | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 1 TP / 4910012807 |
| PFMBA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| PFMPA | < 0.004 µg/L | 0.004 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
| PFNA | < 0.004 µg/L | 0.004 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
| PFOA | < 0.004 µg/L | 0.004 µg/L | 2024-01-16 | Well 8 / 4910012808 |
| PFOS | < 0.004 µg/L | 0.004 µg/L | 2024-01-16 | Well 4 TP / 4910012805 |
| PFPeA | < 0.003 µg/L | 0.003 µg/L | 2024-01-16 | Well 2 TP / 4910012806 |
| PFPeS | < 0.004 µg/L | 0.004 µg/L | 2024-01-16 | Well 8 / 4910012808 |
| PFTA | < 0.008 µg/L | 0.008 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
| PFTrDA | < 0.007 µg/L | 0.007 µg/L | 2024-01-16 | Well 2 TP / 4910012806 |
| PFUnA | < 0.002 µg/L | 0.002 µg/L | 2024-01-16 | Sonoma Co. Water Agency Intertie / 49100012001 |
| lithium | 29 µg/L | 9 µg/L | 2024-01-16 | Well 3 TP / 4910012802 |
Download all EPA UCMR 5 records (CSV)
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 mg/L | 2021-01-01 – 2023-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2018-01-01 – 2020-12-31 | 2026Q3 |
| Lead (PB90) | 0.0084 mg/L | 2015-01-01 – 2017-12-31 | 2026Q3 |
| Lead (PB90) | 0 mg/L | 2012-01-01 – 2014-12-31 | 2026Q3 |
| Lead (PB90) | 0.0041 mg/L | 2009-01-01 – 2011-12-31 | 2026Q3 |
| Lead (PB90) | 0.0034 mg/L | 2006-01-01 – 2008-12-31 | 2026Q3 |
| Lead (PB90) | 0.0034 mg/L | 2008-01-01 – 2008-12-31 | 2026Q3 |
| Lead (PB90) | 0.005 mg/L | 2005-01-01 – 2005-12-31 | 2026Q3 |
| Substance | Published result | Sample date | Location / source |
|---|---|---|---|
| ARSENIC | 8.1 UG/L | 2026-06-09 | WELL 02 / California DDW laboratory results |
| PERFLUOROHEPTANOIC ACID (PFHPA) | < 1.600000000 NG/L | 2026-05-27 | WELL 04 / California DDW laboratory results |
| NETFOSAA | < 1.700000000 NG/L | 2026-05-27 | WELL 08 / California DDW laboratory results |
| NMEFOSAA | < 1.600000000 NG/L | 2026-05-27 | WELL 01 / California DDW laboratory results |
| PERFLUOROOCTANE SULFONIC ACID 6:2 FTS | < 1.600000000 NG/L | 2026-05-27 | WELL 03 / California DDW laboratory results |
| NONAFLUORO NFDHA | < 1.600000000 NG/L | 2026-05-27 | WELL 01 / California DDW laboratory results |
| NMEFOSAA | < 1.600000000 NG/L | 2026-05-27 | WELL 04 / California DDW laboratory results |
| PERFLUORO PFEESA | < 1.600000000 NG/L | 2026-05-27 | WELL 04 / California DDW laboratory results |
| PERFLUORO PFMBA | < 1.700000000 NG/L | 2026-05-27 | WELL 08 / California DDW laboratory results |
| PERFLUOROOCTANE SULFONIC ACID 6:2 FTS | < 1.700000000 NG/L | 2026-05-27 | WELL 02 / California DDW laboratory results |
| PERFLUOROCTANOIC ACID (PFOA) | < 1.700000000 NG/L | 2026-05-27 | WELL 08 / California DDW laboratory results |
| PERFLUOROBUTANE SULFONIC ACID (PFBS) | < 1.700000000 NG/L | 2026-05-27 | WELL 02 / 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
5 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 |
|---|---|---|---|---|
| Lead and Copper Rule Revisions / Notification, Known or Potential LSL | 2025-07-02 – — | Unaddressed | No | 2026Q3 |
| Arsenic Rule / Monitoring, Regular | 2021-04-01 – 2021-06-30 | Resolved | No | 2026Q3 |
| Stage 2 Disinfectants and Disinfection Byproducts Rule / Monitoring, Routine (IDSE) | 2020-01-01 – 2020-12-31 | Resolved | No | 2026Q3 |
| Stage 2 Disinfectants and Disinfection Byproducts Rule / Monitoring, Routine (IDSE) | 2020-01-01 – 2020-12-31 | Resolved | No | 2026Q3 |
| Revised Total Coliform Rule / Monitoring, Routine (RTCR) | 2017-11-01 – 2017-11-30 | Resolved | 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)
Berger, Mike: 707-933-2230
An administrative filing contact may not be a customer-service line. Confirm current contact details with the provider.