EPA UCMR 5 Data · Washington

PFAS Drinking-Water Monitoring Results in Washington

This page summarizes EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5, 2023–2025) drinking-water monitoring records linked to ZIP codes in Washington, as processed for the PFAS Estimator national dataset. Data updated: July 2026.

51.1% of Washington ZIP codes in this dataset (176 total)
had at least one regulated PFAS compound detected at or above its applicable EPA threshold (90 of 176 ZIP codes). Of those, 50 (55.6%) had more than one compound at or above threshold. This dataset includes only ZIP codes with at least one recorded PFAS detection; ZIP codes where all compounds returned non-detect are not represented.
Look up a Washington ZIP code → Full methodology & national data

Compounds detected in Washington

Detection prevalence, exceedance, and concentration by compound, Washington ZIP codes in the EPA UCMR 5 analytic dataset.
Compound Applicable threshold ZIP codes detected At/above threshold Mean detected Maximum detected
PFOA0.004 µg/L (MCL)46 (26.1% of state)46 (100.0%) — all detections at/above limit by construction0.0072 µg/L0.0115 µg/L
PFOS0.004 µg/L (MCL)87 (49.4% of state)87 (100.0%) — all detections at/above limit by construction0.0111 µg/L0.1536 µg/L
PFHxS0.01 µg/L (MCL)83 (47.2% of state)11 (13.3% of detected)0.0076 µg/L0.0558 µg/L
PFNA0.01 µg/L (MCL)1 (0.6% of state)0 (0.0% of detected)0.0043 µg/L0.0043 µg/L
PFBS2.0 µg/L (HI reference)141 (80.1% of state)not calculated¹0.0054 µg/L0.035 µg/L
Lithium7.36 µg/L (reference, not a regulatory limit)45 (25.6% of state)45 (100.0%) at/above reference18.1529 µg/L43.8 µg/L
PFPeA— (no federal limit)83 (47.2% of state)—0.0129 µg/L0.1393 µg/L
PFBA— (no federal limit)22 (12.5% of state)—0.0145 µg/L0.0792 µg/L
PFHpA— (no federal limit)14 (8.0% of state)—0.0038 µg/L0.0058 µg/L
6:2 FTS— (no federal limit)1 (0.6% of state)—0.0095 µg/L0.0095 µg/L

ZIP codes in this dataset (Washington)

176 ZIP codes with at least one recorded PFAS detection. Click a ZIP code to view its full compound-level results.

Per-ZIP-code detection summary for Washington
ZIP code Compounds detected At/above threshold
980015Yes (1)
980021No
980035Yes (1)
980104Yes (1)
980122No
980222No
980235Yes (1)
980294Yes (2)
980302No
980311No
980321No
980333Yes (1)
980385Yes (1)
980426Yes (1)
980514Yes (1)
980523Yes (1)
980535Yes (2)
980551No
980561No
980571No
980582No
980591No
980635Yes (1)
980711No
980722No
980744Yes (2)
980754Yes (2)
980925Yes (1)
981781No
981881No
982231No
982261No
982331No
982396Yes (1)
982722No
982731No
982841No
982962No
983101No
983111No
983121No
983212No
983251No
983371No
983383Yes (2)
983391No
983543No
983581No
983602No
983621No
983663Yes (1)
983674Yes (1)
983681No
983716Yes (2)
983725Yes (2)
983736Yes (2)
983746Yes (2)
983754Yes (2)
983821No
983875Yes (2)
983912No
984022No
984032No
984043No
984052No
984062No
984072No
984082No
984092No
984162No
984182No
984212No
984222No
984242No
984336Yes (2)
984433No
984445Yes (2)
984455Yes (2)
984465Yes (2)
984485Yes (2)
984652No
984662No
984672No
984965Yes (1)
984985Yes (1)
984995Yes (1)
985014Yes (2)
985024Yes (2)
985038Yes (3)
985065Yes (2)
985074Yes (2)
985121No
985133No
985163No
985312Yes (1)
985481No
985951No
986014Yes (2)
986044Yes (2)
986064Yes (2)
986073Yes (2)
986201No
986294Yes (2)
986401No
986424Yes (2)
986606Yes (2)
986616Yes (2)
986626Yes (2)
986634Yes (2)
986646Yes (2)
986656Yes (2)
986686Yes (2)
986713Yes (1)
986741No
986754Yes (2)
986824Yes (2)
986834Yes (2)
986844Yes (2)
986854Yes (2)
986864Yes (2)
988374Yes (2)
988412No
988571No
989011No
989031No
989081No
989301No
989361No
989421No
989441No
989481No
989511No
990015Yes (1)
990033Yes (1)
990044Yes (1)
990053Yes (1)
990065Yes (1)
990091No
990114Yes (2)
990191No
990213Yes (1)
990225Yes (1)
990264Yes (1)
991111No
991631No
991641No
992013Yes (1)
992023Yes (1)
992033Yes (1)
992043Yes (1)
992053Yes (1)
992062No
992073Yes (1)
992083Yes (1)
992124Yes (1)
992165Yes (2)
992174Yes (2)
992183Yes (1)
992234Yes (1)
992243Yes (1)
992583Yes (1)
992603Yes (1)
993205Yes (2)
993241No
993261No
993366Yes (3)
993376Yes (3)
993386Yes (3)
993441No
993491No
993501No
993527Yes (2)
993531No
993547Yes (2)
993621No
994031No

Methodology & limitations

Results are based on EPA UCMR 5 monitoring data (2023–2025), linked to ZIP codes via Public Water System Identifier. Non-detections are not present in this analytic dataset. For each compound and ZIP code, the highest observed concentration across the monitoring period is retained; this characterizes the upper bound of observed drinking-water concentrations, not a long-term average or an individual exposure estimate. A single water system may serve multiple ZIP codes, so the same monitoring record can appear for more than one ZIP in this table. ZIP-code assignment reflects water-system service area geography and does not establish individual household exposure. Private wells are not represented unless served by a monitored public water system. PFOA and PFOS are reported by detection prevalence because the UCMR 5 reporting limit equals their federal MCL. A full PFBS Hazard Index is not calculated because co-located, same-event multi-compound readings are not retained in this dataset. Lithium has no federal Maximum Contaminant Level; 7.36 µg/L is an evidence-based reference concentration from a prospective cohort study, not a regulatory threshold.

Related links

PFAS Estimator homepage & national ZIP lookup
Full national methodology, limitations, and dataset documentation
All states & territories index

Data from the EPA Unregulated Contaminant Monitoring Rule (UCMR 5), 2023–2025. Detection does not indicate a health risk. Not medical advice. Data updated: July 2026. · EPA Source