EPA UCMR 5 Data · Connecticut

PFAS Drinking-Water Monitoring Results in Connecticut

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

98.2% of Connecticut ZIP codes in this dataset (164 total)
had at least one regulated PFAS compound detected at or above its applicable EPA threshold (161 of 164 ZIP codes). Of those, 147 (91.3%) 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 Connecticut ZIP code → Full methodology & national data

Compounds detected in Connecticut

Detection prevalence, exceedance, and concentration by compound, Connecticut 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)159 (97.0% of state)159 (100.0%) — all detections at/above limit by construction0.0077 µg/L0.0159 µg/L
PFOS0.004 µg/L (MCL)149 (90.9% of state)149 (100.0%) — all detections at/above limit by construction0.0094 µg/L0.0162 µg/L
PFHxS0.01 µg/L (MCL)68 (41.5% of state)13 (19.1% of detected)0.0056 µg/L0.0125 µg/L
PFBS2.0 µg/L (HI reference)141 (86.0% of state)not calculated¹0.0045 µg/L0.015 µg/L
Lithium7.36 µg/L (reference, not a regulatory limit)26 (15.9% of state)26 (100.0%) at/above reference16.6119 µg/L22.2 µg/L
PFPeA— (no federal limit)147 (89.6% of state)—0.0044 µg/L0.0191 µg/L
PFBA— (no federal limit)61 (37.2% of state)—0.0068 µg/L0.0121 µg/L
PFHpA— (no federal limit)37 (22.6% of state)—0.0037 µg/L0.0054 µg/L

ZIP codes in this dataset (Connecticut)

164 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 Connecticut
ZIP code Compounds detected At/above threshold
060016Yes (2)
060105Yes (2)
060132Yes (2)
060167Yes (2)
060192Yes (2)
060264Yes (2)
060297Yes (2)
060326Yes (2)
060336Yes (2)
060354Yes (2)
060376Yes (2)
060406Yes (2)
060428Yes (2)
060535Yes (2)
060626Yes (2)
060668Yes (2)
060705Yes (2)
060717Yes (2)
060748Yes (2)
060787Yes (2)
060827Yes (2)
060847Yes (2)
060855Yes (2)
060887Yes (2)
060895Yes (2)
060924Yes (2)
060937Yes (2)
060967Yes (2)
062344Yes (2)
062394Yes (2)
062414Yes (2)
062495Yes (3)
062545Yes (3)
062605Yes (2)
062634Yes (2)
062687Yes (2)
062697Yes (2)
062775Yes (2)
062815Yes (2)
063335Yes (2)
063345Yes (3)
063385Yes (1)
063516Yes (3)
063535Yes (3)
063551No
063575Yes (2)
063605Yes (3)
063655Yes (3)
063781No
063796Yes (2)
063805Yes (3)
063825Yes (3)
063895Yes (3)
064014Yes (2)
064035Yes (2)
064054Yes (2)
064084Yes (2)
064106Yes (3)
064114Yes (2)
064136Yes (2)
064152Yes (1)
064162Yes (1)
064184Yes (2)
064376Yes (2)
064436Yes (2)
064447Yes (2)
064506Yes (2)
064516Yes (2)
064556Yes (2)
064576Yes (2)
064604Yes (2)
064614Yes (2)
064677Yes (2)
064686Yes (2)
064707Yes (2)
064714Yes (2)
064724Yes (2)
064735Yes (3)
064756Yes (2)
064774Yes (2)
064785Yes (2)
064797Yes (2)
064801No
064827Yes (2)
064835Yes (2)
064846Yes (2)
064882Yes (1)
064898Yes (2)
064926Yes (3)
064986Yes (2)
065014Yes (2)
065024Yes (2)
065034Yes (2)
065044Yes (2)
065054Yes (2)
065064Yes (2)
065074Yes (2)
065084Yes (2)
065094Yes (2)
065104Yes (2)
065114Yes (2)
065124Yes (2)
065134Yes (2)
065144Yes (2)
065154Yes (2)
065164Yes (2)
065174Yes (2)
065184Yes (2)
065194Yes (2)
065204Yes (2)
065214Yes (2)
065244Yes (2)
065254Yes (2)
065304Yes (2)
065314Yes (2)
065324Yes (2)
065334Yes (2)
065344Yes (2)
065354Yes (2)
065364Yes (2)
065374Yes (2)
065384Yes (2)
065404Yes (2)
066046Yes (2)
066056Yes (2)
066066Yes (2)
066076Yes (2)
066086Yes (2)
066106Yes (2)
066116Yes (2)
066126Yes (2)
066146Yes (2)
066156Yes (2)
067165Yes (2)
067554Yes (2)
067622Yes (1)
067764Yes (2)
067944Yes (2)
068013Yes (1)
068044Yes (2)
068073Yes (2)
068103Yes (1)
068113Yes (1)
068203Yes (1)
068246Yes (2)
068256Yes (2)
068303Yes (2)
068313Yes (2)
068405Yes (2)
068505Yes (2)
068515Yes (2)
068555Yes (2)
068703Yes (2)
068777Yes (2)
068783Yes (2)
068807Yes (2)
068836Yes (2)
068906Yes (2)
068977Yes (2)
069012Yes (1)
069032Yes (1)
069052Yes (1)
069062Yes (1)
069072Yes (1)

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