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Community Water System · PWS CA4310014

City of Sunnyvale

Sunnyvale, California 94088 - drinking water served from surface water sources to 157,566 people, tracked in EPA SDWIS and UCMR5.

157,566
People served
145
EPA violations
10
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 145 drinking-water violations at City of Sunnyvale, 7% of them health-based - above the California per-system average.

145
Total EPA violations on record
7%
Health-based (MCL / treatment failure)
157,566
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: City of Sunnyvale

City of Sunnyvale is a local-owned community water system that delivers drinking water to 157,566 residents in Sunnyvale, California (Santa Clara County) through 28,372 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 145 total violations for this system , of which 10 (7%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 131 monitoring and reporting violations are on file. The most recent violation on record dates to 2015.

The most frequently cited contaminant at this system is Surface Water Treatment Rule, recorded in 10 violations (TT, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across California, EPA tracks 7,249 public water systems serving 42,404,883 people, with 153,308 cumulative violations and 63,983 health-based violations on record. About 89% of systems in the state carry at least one violation, and state-wide the average per system is 21.1 violations. Statewide, 447 of 694 UCMR5-tested systems have reported PFAS detections (64.4%).

City of Sunnyvale's 145 violations sit above the California average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
157,566
Total Violations
145
Health-Based Violations
10
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
28,372
County
Santa Clara
School/Daycare
No
MCL Violations
0
Monitoring Violations
131
Treatment Tech Violations
10

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Surface Water Treatment Rule TT 10 2015
Lead and Copper Rule MR 3 1992
Arsenic MR 2 2015
Fluoride MR 2 2015
Mercury MR 2 2015
Nitrite MR 2 2015
Thallium, Total MR 2 2015
cis-1,2-Dichloroethylene MR 2 2015
DICHLOROMETHANE MR 2 2015
o-Dichlorobenzene MR 2 2015
trans-1,2-Dichloroethylene MR 2 2015
1,1,1-Trichloroethane MR 2 2015
Trichloroethylene MR 2 2015
Benzene MR 2 2015
Endrin MR 2 2015
Methoxychlor MR 2 2015
Endothall MR 2 2015
Glyphosate MR 2 2015
Di(2-ethylhexyl) adipate MR 2 2015
Di(2-ethylhexyl) phthalate MR 2 2015
Picloram MR 2 2015
Dinoseb MR 2 2015
Hexachlorocyclopentadiene MR 2 2015
Carbofuran MR 2 2015
LASSO MR 2 2015
2,3,7,8-TCDD MR 2 2015
Heptachlor MR 2 2015
2,4-D MR 2 2015
HEXACHLOROBENZENE MR 2 2015
Pentachlorophenol MR 2 2015

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 580 samples detected PFAS.

Contaminant Date Result MRL Status
HFPO-DA 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
PFOS 7/29/2024 <4.00 ppt 4.00 ppt Not Detected
PFHpS 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 7/29/2024 <4.00 ppt 4.00 ppt Not Detected
NFDHA 7/29/2024 <20.00 ppt 20.00 ppt Not Detected
PFEESA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFBA 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
ADONA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
PFHxA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFDoA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFDA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFBS 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
PFMPA 7/29/2024 <4.00 ppt 4.00 ppt Not Detected
PFNA 7/29/2024 <4.00 ppt 4.00 ppt Not Detected
PFUnA 7/29/2024 <2.00 ppt 2.00 ppt Not Detected
PFTA 7/29/2024 <8.00 ppt 8.00 ppt Not Detected
PFOA 7/29/2024 <4.00 ppt 4.00 ppt Not Detected
6:2 FTS 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 7/29/2024 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 7/29/2024 <7.00 ppt 7.00 ppt Not Detected
PFPeA 7/29/2024 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 7/29/2024 <5.00 ppt 5.00 ppt Not Detected
9Cl-PF3ONS 7/29/2024 <2.00 ppt 2.00 ppt Not Detected
PFHpA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFNA 7/17/2024 <4.00 ppt 4.00 ppt Not Detected
PFOS 7/17/2024 <4.00 ppt 4.00 ppt Not Detected
PFOA 7/17/2024 <4.00 ppt 4.00 ppt Not Detected
PFHxA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFDoA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFBS 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 7/17/2024 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 7/17/2024 <5.00 ppt 5.00 ppt Not Detected
9Cl-PF3ONS 7/17/2024 <2.00 ppt 2.00 ppt Not Detected
8:2 FTS 7/17/2024 <5.00 ppt 5.00 ppt Not Detected
PFDA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpS 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 7/17/2024 <4.00 ppt 4.00 ppt Not Detected
NFDHA 7/17/2024 <20.00 ppt 20.00 ppt Not Detected
PFEESA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 7/17/2024 <3.00 ppt 3.00 ppt Not Detected
PFMPA 7/17/2024 <4.00 ppt 4.00 ppt Not Detected
PFBA 7/17/2024 <5.00 ppt 5.00 ppt Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for City of Sunnyvale.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID CA4310014 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

California Drinking Water Authority

California State Water Resources Control Board, Division of Drinking Water is the primacy agency that licenses and inspects City of Sunnyvale under EPA-delegated authority.

Open CA regulator portal

Source: California State Water Resources Control Board, Division of Drinking Water

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2015 Surface Water Treatment Rule TT 10 SDWIS / CA4310014 / 0200
2015 Arsenic MR 2 SDWIS / CA4310014 / 1005
2015 Fluoride MR 2 SDWIS / CA4310014 / 1025
2015 Mercury MR 2 SDWIS / CA4310014 / 1035
2015 Nitrite MR 2 SDWIS / CA4310014 / 1041
2015 Thallium, Total MR 2 SDWIS / CA4310014 / 1085
2015 cis-1,2-Dichloroethylene MR 2 SDWIS / CA4310014 / 2380
2015 DICHLOROMETHANE MR 2 SDWIS / CA4310014 / 2964
2015 o-Dichlorobenzene MR 2 SDWIS / CA4310014 / 2968
2015 trans-1,2-Dichloroethylene MR 2 SDWIS / CA4310014 / 2979
2015 1,1,1-Trichloroethane MR 2 SDWIS / CA4310014 / 2981
2015 Trichloroethylene MR 2 SDWIS / CA4310014 / 2984
2015 Benzene MR 2 SDWIS / CA4310014 / 2990
2015 Endrin MR 2 SDWIS / CA4310014 / 2005
2015 Methoxychlor MR 2 SDWIS / CA4310014 / 2015

How City of Sunnyvale Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric City of Sunnyvale California avg Federal benchmark
Total violations 145 21.1 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 10 8.8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 64.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 157,566 5,850 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 7,249 regulated public water systems in California.

Federal MCL reference, Safe Drinking Water Act thresholds
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is City of Sunnyvale water safe to drink?
City of Sunnyvale (PWS ID: CA4310014) has 145 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 157,566 people using Surface Water sources.
How many people does City of Sunnyvale serve?
City of Sunnyvale serves 157,566 people in Sunnyvale, California. It is a Local-owned system using Surface Water water sources with 28,372 service connections.
What type of violations does City of Sunnyvale have?
City of Sunnyvale has 145 total violations: 10 health-based violations (MCL exceedances or treatment failures), 131 monitoring/reporting violations, and 10 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in City of Sunnyvale water?
No. City of Sunnyvale was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does City of Sunnyvale use?
City of Sunnyvale uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from?
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.