CA / Sonora
CA · Tap water records
Sonora tap water, in plain English
Here is what the EPA's own data shows about tap water in Sonora. According to EPA SDWIS data retrieved June 2026, Sonora is served by 14 active community water systems, together reported to serve about 37,743 people.
As of June 2026, EPA records show 30 violations across the community water system(s) serving Sonora, going back to the earliest EPA record. 5 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Tud - Upper Basin Water System
13,280 served · surface water · PWSID CA5510012 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Tud - Sonora/Jamestown Water System
11,054 served · surface water · PWSID CA5510001 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Tud - Columbia Water System
5,463 served · surface water · PWSID CA5510013 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Tud - Ponderosa
1,767 served · surface water · PWSID CA5510002 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 1996. All have since returned to compliance, per EPA records.
Tud - Tuolumne Water System
1,761 served · surface water · PWSID CA5510003 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Phoenix Lake Estates Cc Mwc
1,168 served · groundwater · PWSID CA5510026 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between January 1996 and January 2006. All have since returned to compliance, per EPA records.
Sonora Meadows Mutual Wtr Co
1,123 served · surface water · PWSID CA5510023 - Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in January 2015. The EPA record lists a level of 0.062 MG/L; the limit (MCL) is 0.06 MG/L. All have since returned to compliance, per EPA records.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
- Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2021. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between July 1993 and January 1996. All have since returned to compliance, per EPA records.
Tud-Apple Valley Estates
826 served · groundwater · PWSID CA5510028 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 1996. All have since returned to compliance, per EPA records.
Belleview Oaks Mutual Water Co
468 served · groundwater · PWSID CA5500042 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Slide Inn Snowbowl Water Co
417 served · groundwater · PWSID CA5500077 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Golden Sierra Estates_fka Mother Lode
210 served · groundwater · PWSID CA5500125 - Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Tud-Peaceful Pines Water System
92 served · groundwater · PWSID CA5510021 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Tud-Wards Ferry Ranches
62 served · groundwater · PWSID CA5500363 - Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in August 2003. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
Ponderosa Mobile Home Park
52 served · groundwater · PWSID CA5500092 - Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in July 2016. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. All have since returned to compliance, per EPA records.
- Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 1993. All have since returned to compliance, per EPA records.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.