CA / San Jose
CA · Tap water records
San Jose tap water, in plain English
Here is what the EPA's own data shows about tap water in San Jose. According to EPA SDWIS data retrieved June 2026, San Jose is served by 68 active community water systems, together reported to serve about 3,389,570 people.
As of June 2026, EPA records show 146 violations across the community water system(s) serving San Jose, going back to the earliest EPA record. 79 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
San Jose Water
1,039,920 served · surface water · PWSID CA4310011 - Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 4 times in June 2023. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Perchlorate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2019. All have since returned to compliance, per EPA records.
- Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in April 2017. All have since returned to compliance, per EPA records.
Cws - Bakersfield
267,881 served · surface water · PWSID CA1510003 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service - Stockton
176,266 served · surface water · PWSID CA3910001 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Bakersfield, City Of
160,144 served · surface water · PWSID CA1510031 - Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2001. All have since returned to compliance, per EPA records.
California Water Service Co. - Ela
152,474 served · surface water · PWSID CA1910036 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - Visalia
148,496 served · groundwater · PWSID CA5410016 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co. - Dominguez
143,996 served · surface water · PWSID CA1910033 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between January 2018 and April 2018. All have since returned to compliance, per EPA records.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between January 2018 and April 2018. All have since returned to compliance, per EPA records.
Cwsc Salinas
123,679 served · groundwater · PWSID CA2710010 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cal-Water Service Co.-Chico
114,925 served · groundwater · PWSID CA0410002 - Health-based Tetrachloroethylene: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 4 times in December 1998. The EPA record lists a level of 0.032 MG/L; the limit (MCL) is 0.005 MG/L. All have since returned to compliance, per EPA records.
Great Oaks Wc Inc
110,088 served · groundwater · PWSID CA4310022 - 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 2002. All have since returned to compliance, per EPA records.
California Water Service - San Mateo
102,348 served · surface water · PWSID CA4110008 - Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in October 1992. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
City Of San Jose - Evg/Edv/Coy
101,265 served · surface water · PWSID CA4310020 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co. - Herm/Redo
96,853 served · surface water · PWSID CA1910134 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co. - Palos Ver
71,452 served · surface water · PWSID CA1910104 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cwsc Los Altos Suburban
69,973 served · surface water · PWSID CA4310001 - Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in November 1992. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
California Water Service-S San Francisco
64,146 served · surface water · PWSID CA4110009 - Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in October 1992. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in June 2013. All have since returned to compliance, per EPA records.
California Water Service - Bear Gulch
61,431 served · surface water · PWSID CA4110006 - Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in October 1992. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
California Water Service - Livermore
60,414 served · surface water · PWSID CA0110003 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
City Of San Jose - Nsj/Alviso
45,559 served · surface water · PWSID CA4310019 - Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in December 2005. All have since returned to compliance, per EPA records.
Hawthorne-City Water Dept.
44,718 served · surface water · PWSID CA1910047 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2019. All have since returned to compliance, per EPA records.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2019. All have since returned to compliance, per EPA records.
California Water Service - San Carlos
35,344 served · surface water · PWSID CA4110007 - Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in March 2015. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
Cws - Selma
26,517 served · groundwater · PWSID CA1010024 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - North Garden
22,762 served · surface water · PWSID CA1510055 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co - Westlake
19,533 served · surface water · PWSID CA5610016 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co.-Travis Afb
18,111 served · surface water · PWSID CA4810701 - Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in July 2015. The EPA record lists a level of 0.09 MG/L; the limit (MCL) is 0.08 MG/L. All have since returned to compliance, per EPA records.
City Of Cupertino
16,336 served · surface water · PWSID CA4310018 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cwsc King City
16,334 served · groundwater · PWSID CA2710009 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cal-Water Service Co.-Marysville
12,419 served · groundwater · PWSID CA5810001 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cal-Water Service Co.-Oroville
11,106 served · surface water · PWSID CA0410005 - Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2022. All have since returned to compliance, per EPA records.
California Water Service Co. - Dixon
10,623 served · groundwater · PWSID CA4810002 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cal-Water Service Co.-Willows
7,240 served · groundwater · PWSID CA1110003 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cwsc Salinas Hills
5,293 served · groundwater · PWSID CA2710012 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Commerce-City, Water Dept.
4,205 served · surface water · PWSID CA1910050 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Tesoro Viejo Master Mwc, Inc.
3,885 served · surface water · PWSID CA2010017 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cwsc Oak Hills
3,161 served · groundwater · PWSID CA2710019 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - Kernville
2,572 served · surface water · PWSID CA1510033 - Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 48 times between January 2016 and October 2019. The EPA record lists a level of 0.074 MG/L; the limit (MCL) is 0.06 MG/L. All have since returned to compliance, per EPA records.
Lucerne Water Co. - Cal Water Service
2,129 served · surface water · PWSID CA1710005 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cwsc Las Lomas
2,084 served · groundwater · PWSID CA2710013 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cal-Water Service Co.-Hamilton City
1,799 served · groundwater · PWSID CA1110002 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co.-Lancaster
1,387 served · surface water · PWSID CA1910010 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2014. All have since returned to compliance, per EPA records.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2014. All have since returned to compliance, per EPA records.
Cws Southlake System
1,112 served · groundwater · PWSID CA1510039 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Westfield Garden Mobile Home Park
942 served · groundwater · PWSID TX1011947 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co-Lake Hughes
929 served · groundwater · PWSID CA1910242 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
California Water Service Co-Leona Valley
878 served · surface water · PWSID CA1910243 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - Lower Bodfish Water System
736 served · groundwater · PWSID CA1510056 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - Tulco Water Company
716 served · groundwater · PWSID CA5410041 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cedar Grove Mobile Home Park
595 served · surface water · PWSID TX0500043 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Mission Oaks Mobile Home Park
550 served · groundwater · PWSID CA3510006 - Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2002 and July 2008. 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 July 1993. All have since returned to compliance, per EPA records.
Riverbend Mhp
500 served · surface water · PWSID OK3007232 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Armstrong Valley-Cal Water Service (Puc)
473 served · groundwater · PWSID CA4910018 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Coast Springs - Cal. Water Service (Puc)
388 served · surface water · PWSID CA2110007 - 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.
Cws - Upper Bodfish Water System
307 served · groundwater · PWSID CA1510026 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Mt. Pleasant Water Users Association
300 served · surface water · PWSID CA4300563 - 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 2000 and October 2017. All have since returned to compliance, per EPA records.
- Monitoring Chloramine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2013. All have since returned to compliance, per EPA records.
Cws - Lakeland
294 served · groundwater · PWSID CA1510049 - Health-based Fluoride: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in July 2002. The EPA record lists a level of 3.8 MG/L; the limit (MCL) is 2 MG/L. All have since returned to compliance, per EPA records.
- Health-based Combined Radium (-226 and -228): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in July 2002. The EPA record lists a level of 7.14 PCI/L; the limit (MCL) is 5 PCI/L. All have since returned to compliance, per EPA records.
Cws-Onyx Water System
284 served · groundwater · PWSID CA1510043 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws-Split Mountain Water System
226 served · surface water · PWSID CA1500407 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Longhorn Mobile Home Community
220 served · groundwater · PWSID TX1010587 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws - Fremont Valley
167 served · groundwater · PWSID CA1500333 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Bella Lago Mobile Home Park
152 served · groundwater · PWSID CA1700610 - 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.
- 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 2024. 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 June 2017. All have since returned to compliance, per EPA records.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2000. All have since returned to compliance, per EPA records.
Roseview Heights Mutual Water Company
148 served · surface water · PWSID CA4300562 - 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.
- 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 3 times between January 1998 and January 2001. All have since returned to compliance, per EPA records.
Kennon Water Company
142 served · surface water · PWSID CA4300521 - 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.
- 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 January 1999. All have since returned to compliance, per EPA records.
Cws - Mullen Water Company
138 served · groundwater · PWSID CA5400935 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Cws-Grand Oaks Water System
122 served · groundwater · PWSID CA1500374 - Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in March 1996. All have since returned to compliance, per EPA records.
Rancho Del Paradiso-Cal Water Svc (Puc)
94 served · groundwater · PWSID CA4900514 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Lake San Antonio Mhp Ws
84 served · groundwater · PWSID CA2701906 - 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 2018 and July 2019. EPA records do not show all of these as returned to compliance.
Hawkins Water Co-Cal Water Service (Puc)
81 served · groundwater · PWSID CA4900546 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Noel Heights-Cal Water Service (Puc)
79 served · surface water · PWSID CA4900785 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Aborn Heights Water Mutual Association
45 served · groundwater · PWSID CA4300792 - 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 July 2025. 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 January 1999. All have since returned to compliance, per EPA records.
- Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in May 1998. 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.