Washington County Water Quality: 6 Cities Ranked by the Records
Washington County, Oregon: 6 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
Highest result for each contaminant
One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.
Lead (90th percentile)Detected in 4 systems of 6 tested15 µg/L federal action level · US EPAHighest4.93 µg/L
- TUALATIN, CITY OF4.93 µg/LMonitoring period: 2025–2025
- FOREST GROVE, CITY OF3.6 µg/LMonitoring period: 2024–2026 (still open)
- BEAVERTON, CITY OF2.6 µg/LMonitoring period: 2024–2024
- SHERWOOD, CITY OF1.3 µg/LMonitoring period: 2023–2025
- CORNELIUS, CITY OFNot detectedMonitoring period: 2021–2023
- HILLSBORO, CITY OFNot detectedMonitoring period: 2022–2024
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)Detected in 1 system of 6 testedNo federal or state limit; shown for transparencyHighest8 ng/L
- SHERWOOD, CITY OF8 ng/LSample date: 2024-09-25 to 2025-06-12
- BEAVERTON, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-17 to 2024-06-25
- CORNELIUS, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-05-28 to 2025-01-13
- FOREST GROVE, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-10 to 2024-04-08
- HILLSBORO, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-12 to 2024-04-02
- TUALATIN, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-01-22 to 2024-10-07
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)Detected in 1 system of 6 testedNo federal or state limit; shown for transparencyHighest41.3 ng/L
- SHERWOOD, CITY OF41.3 ng/LSample date: 2024-09-25 to 2025-06-12
- BEAVERTON, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-17 to 2024-06-25
- CORNELIUS, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-05-28 to 2025-01-13
- FOREST GROVE, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-10 to 2024-04-08
- HILLSBORO, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-12 to 2024-04-02
- TUALATIN, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-01-22 to 2024-10-07
28 substances tested, none detected in any systemShow
Tested in these 6 systems: BEAVERTON, CITY OF, CORNELIUS, CITY OF, FOREST GROVE, CITY OF, HILLSBORO, CITY OF, SHERWOOD, CITY OF, TUALATIN, CITY OF
- 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
- 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
- 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
- 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
- Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
- Lithium
- N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
- N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
- Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
- Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
- Perfluoro-3-methoxypropanoic acid (PFMPA)
- Perfluoro-4-methoxybutanoic acid (PFMBA)
- Perfluorobutanesulfonic acid (PFBS)
- Perfluorobutanoic acid (PFBA)
- Perfluorodecanoic acid (PFDA)
- Perfluorododecanoic acid (PFDoA)
- Perfluoroheptanesulfonic acid (PFHpS)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorohexanesulfonic acid (PFHxS)
- Perfluorohexanoic acid (PFHxA)
- Perfluorononanoic acid (PFNA)
- Perfluorooctanesulfonic acid (PFOS)
- Perfluorooctanoic acid (PFOA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluoropentanoic acid (PFPeA)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
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Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.
0of 6 cities above the 15 µg/L action level
Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.
Lead in OregonLargest water systems
- HillsboroHILLSBORO, CITY OF · OR410151392,632 served
- BeavertonBEAVERTON, CITY OF · OR410008188,045 served
- TualatinTUALATIN, CITY OF · OR410090628,106 served
- Forest GroveFOREST GROVE, CITY OF · OR410030526,838 served
- SherwoodSHERWOOD, CITY OF · OR410081620,781 served
- CorneliusCORNELIUS, CITY OF · OR410021814,490 served
Frequently asked
How does Washington County tap water compare across cities?
PurityMap ranks 6 cities in Washington County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Hillsboro's main water system: HILLSBORO, CITY OF · PWSID OR4101513 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.
How many Washington County cities had a PFAS sample above a 2024 EPA limit?
None of the 6 Washington County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 1.
Is there lead in Washington County tap water?
Utilities report lead as a 90th-percentile result from home taps. 4 of 6 Washington County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.
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