PlainWater
States → Oregon

CORNELIUS, CITY OF

PWS ID: OR4100218 · CORNELIUS, Oregon 97113-8912

CORNELIUS, CITY OF serves 14,490 people in CORNELIUS, Oregon using Surface Water water sources. It has 42 recorded EPA violations, including 0 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: CORNELIUS, CITY OF

CORNELIUS, CITY OF is a local-owned community water system that delivers drinking water to 14,490 residents in CORNELIUS, Oregon (Washington County) through 4,153 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 42 total violations for this system , of which 0 (0%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 35 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 17 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across Oregon, EPA tracks 2,518 public water systems serving 4,005,242 people, with 206,659 cumulative violations and 20,339 health-based violations on record. About 99% of systems in the state carry at least one violation, and state-wide the average per system is 82.1 violations. CORNELIUS, CITY OF's 42 violations sit below the Oregon average. Statewide, 30 of 125 UCMR5-tested systems have reported PFAS detections (24%). 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
14,490
Total Violations
42
Health-Based Violations
0
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
4,153
County
Washington
School/Daycare
No
MCL Violations
0
Monitoring Violations
35
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 17 2013
Consumer Confidence Rule Other 7 2023
TTHM MR 5 2022
Total Haloacetic Acids (HAA5) MR 5 2022
Lead and Copper Rule MR 2 2005
Combined Radium (-226 and -228) MR 1 2020
Gross Alpha, Excl. Radon and U MR 1 2020
COLIPHAGE MR 1 2024
DICHLOROMETHANE MR 1 2022
Revised Total Coliform Rule MON 1 2018
Combined Uranium MR 1 2020

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 150 samples detected PFAS.

Contaminant Date Result MRL Status
lithium 7/31/2024 <9 µg/L 9 µg/L Not Detected
PFHpA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
4:2 FTS 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFMBA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFBS 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFHxS 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFNA 7/31/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFTA 7/31/2024 <0.008 µg/L 0.008 µg/L Not Detected
PFHpS 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 7/31/2024 <0.004 µg/L 0.004 µg/L Not Detected
NFDHA 7/31/2024 <0.02 µg/L 0.02 µg/L Not Detected
PFEESA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
NMeFOSAA 7/31/2024 <0.006 µg/L 0.006 µg/L Not Detected
PFUnA 7/31/2024 <0.002 µg/L 0.002 µg/L Not Detected
PFTrDA 7/31/2024 <0.007 µg/L 0.007 µg/L Not Detected
PFOS 7/31/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFOA 7/31/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFPeA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFDA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFMPA 7/31/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFHxA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
11Cl-PF3OUdS 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
9Cl-PF3ONS 7/31/2024 <0.002 µg/L 0.002 µg/L Not Detected
ADONA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
HFPO-DA 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
NEtFOSAA 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
PFBA 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
6:2 FTS 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
8:2 FTS 7/31/2024 <0.005 µg/L 0.005 µg/L Not Detected
PFDoA 7/31/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFBA 5/28/2024 <0.005 µg/L 0.005 µg/L Not Detected
PFHpS 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 5/28/2024 <0.004 µg/L 0.004 µg/L Not Detected
NFDHA 5/28/2024 <0.02 µg/L 0.02 µg/L Not Detected
PFEESA 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFMBA 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFPeA 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFMPA 5/28/2024 <0.004 µg/L 0.004 µg/L Not Detected
8:2 FTS 5/28/2024 <0.005 µg/L 0.005 µg/L Not Detected
HFPO-DA 5/28/2024 <0.005 µg/L 0.005 µg/L Not Detected
6:2 FTS 5/28/2024 <0.005 µg/L 0.005 µg/L Not Detected
ADONA 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
9Cl-PF3ONS 5/28/2024 <0.002 µg/L 0.002 µg/L Not Detected
4:2 FTS 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
PFUnA 5/28/2024 <0.002 µg/L 0.002 µg/L Not Detected
PFOS 5/28/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFHxA 5/28/2024 <0.003 µg/L 0.003 µg/L Not Detected
11Cl-PF3OUdS 5/28/2024 <0.005 µg/L 0.005 µg/L Not Detected
PFNA 5/28/2024 <0.004 µg/L 0.004 µg/L Not Detected
PFBS 5/28/2024 <0.003 µg/L 0.003 µg/L 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 CORNELIUS, CITY OF.

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 OR4100218 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Oregon Drinking Water Authority

Oregon's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find OR regulator via EPA SDWIS

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
2024 COLIPHAGE MR 1 SDWIS / OR4100218 / 3028
2023 Consumer Confidence Rule Other 7 SDWIS / OR4100218 / 7000
2022 TTHM MR 5 SDWIS / OR4100218 / 2950
2022 Total Haloacetic Acids (HAA5) MR 5 SDWIS / OR4100218 / 2456
2022 DICHLOROMETHANE MR 1 SDWIS / OR4100218 / 2964
2020 Combined Radium (-226 and -228) MR 1 SDWIS / OR4100218 / 4010
2020 Gross Alpha, Excl. Radon and U MR 1 SDWIS / OR4100218 / 4000
2020 Combined Uranium MR 1 SDWIS / OR4100218 / 4006
2018 Revised Total Coliform Rule MON 1 SDWIS / OR4100218 / 8000
2013 Coliform (TCR) MR 17 SDWIS / OR4100218 / 3100
2005 Lead and Copper Rule MR 2 SDWIS / OR4100218 / 5000

How CORNELIUS, CITY OF Compares

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

Metric CORNELIUS, CITY OF Oregon avg Federal benchmark
Total violations 42 82.1 SDWA compliance — any non-zero count is a recorded breach
Health-based violations 0 8.1 Indicates a contaminant exceeded a federal MCL
PFAS detection None 24% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 14,490 1,591 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,518 regulated public water systems in Oregon.

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
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is CORNELIUS, CITY OF water safe to drink? ▼
CORNELIUS, CITY OF (PWS ID: OR4100218) has 42 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 14,490 people using Surface Water sources.
How many people does CORNELIUS, CITY OF serve? ▼
CORNELIUS, CITY OF serves 14,490 people in CORNELIUS, Oregon. It is a Local-owned system using Surface Water water sources with 4,153 service connections.
What type of violations does CORNELIUS, CITY OF have? ▼
CORNELIUS, CITY OF has 42 total violations: 0 health-based violations (MCL exceedances or treatment failures), 35 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in CORNELIUS, CITY OF water? ▼
No. CORNELIUS, CITY OF was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does CORNELIUS, CITY OF use? ▼
CORNELIUS, CITY OF 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.

Explore PlainWater

Water in Oregon

All systems in state
All States

Water quality by state
Contaminants

PFAS & other pollutants
Guides

Understanding water quality

Related Data for Oregon

Environmental Data → Natural Hazards → Air Quality → Healthcare Access → Climate Data →
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.

Read our methodology — how this data is sourced, computed, and verified.

Related

Browse all → | Rankings →
Data sourced from $official public datasets. See our methodology for details. Retrieved and formatted by PlainWater Editorial