{"schemaVersion":2,"id":"us-MA3056000","communeId":"MA3056000","name":"Chelmsford Water District","slug":"chelmsford-water-district-ma3056000","country":"us","region":"Massachusetts","supplier":"CHELMSFORD WATER DISTRICT","networks":[{"code":"00009/1305","name":"Entry Point to Dist. System (Riverneck WTP)"},{"code":"00042/11949","name":"Entry Point to Dist. System (Smith Street Wells GWTP)"},{"code":"06810/10001","name":"Entry Point to Dist. System (Crooked Spring WTP)"},{"code":"10071/10071","name":"Entry Point to Dist. System (\"Mill Road Wells (1R, 2R, 3)\")"}],"latestSampleDate":"2024-10-08T00:00:00Z","conformity":{"conclusion":null,"bacteriological":"unknown","chemical":"unknown"},"source":{"name":"U.S. Environmental Protection Agency, Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) occurrence data, final dataset (August 2026)","url":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","license":"Public domain (U.S. federal government work, 17 U.S.C. § 105)","kind":"open_data_file","verified":true,"retrievedAt":"2026-09-19T19:22:35.464Z","note":"UCMR 5 results do not indicate compliance or noncompliance with the PFAS drinking water standards. Samples are taken at the entry point to the distribution system, not at the tap; the system may have changed sources or installed treatment since. Treatment reported to EPA for PFAS: granular activated carbon (GAC). 4 entry points sampled, 10 sampling events between 2023-10-12 and 2024-10-08. The page's PFAS values come from the newest sample at Entry Point to Dist. System (Crooked Spring WTP) (06810/10001), the entry point with the highest PFOA + PFOS + PFNA + PFHxS sum; the other entry points' maxima are listed as separate rows. Non-detects are shown as \"<\" followed by EPA's minimum reporting level (3 to 20 ng/L); PFAS-4 sums quantified compounds only, so it is a lower bound when a compound was not detected. Registry (name, population, counties, ZIPs) from EPA SDWIS/ECHO; service-area centroid from EPA ORD."},"pfas":{"status":"measured","sum20":null,"pfas4":{"value":null,"valueText":"<0.015","unit":"µg/L","limit":0.004,"limitUnit":"µg/L","status":"ok","sampleDate":"2024-04-09T00:00:00Z","sampleId":"810-100147-1","nonDetect":true,"upperBound":0.015},"pfas4DetectedCount":0,"lowerBound":true,"sampledAt":{"commune":"MA3056000","name":"Entry Point to Dist. System (Crooked Spring WTP)","network":"06810/10001"},"qualifiers":[{"name":"PFOA","valueText":"<0.004","unit":"µg/L"},{"name":"PFOS","valueText":"<0.004","unit":"µg/L"},{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"},{"name":"HFPO-DA","valueText":"<0.005","unit":"µg/L"},{"name":"PFBS","valueText":"<0.003","unit":"µg/L"},{"name":"11Cl-PF3OUdS","valueText":"<0.005","unit":"µg/L"},{"name":"4:2 FTS","valueText":"<0.003","unit":"µg/L"},{"name":"6:2 FTS","valueText":"<0.005","unit":"µg/L"},{"name":"8:2 FTS","valueText":"<0.005","unit":"µg/L"},{"name":"9Cl-PF3ONS","valueText":"<0.002","unit":"µg/L"},{"name":"ADONA","valueText":"<0.003","unit":"µg/L"},{"name":"NEtFOSAA","valueText":"<0.005","unit":"µg/L"},{"name":"NFDHA","valueText":"<0.02","unit":"µg/L"},{"name":"NMeFOSAA","valueText":"<0.006","unit":"µg/L"},{"name":"PFBA","valueText":"<0.005","unit":"µg/L"},{"name":"PFDA","valueText":"<0.003","unit":"µg/L"},{"name":"PFDoA","valueText":"<0.003","unit":"µg/L"},{"name":"PFEESA","valueText":"<0.003","unit":"µg/L"},{"name":"PFHpA","valueText":"<0.003","unit":"µg/L"},{"name":"PFHpS","valueText":"<0.003","unit":"µg/L"},{"name":"PFHxA","valueText":"<0.003","unit":"µg/L"},{"name":"PFMBA","valueText":"<0.003","unit":"µg/L"},{"name":"PFMPA","valueText":"<0.004","unit":"µg/L"},{"name":"PFPeA","valueText":"<0.003","unit":"µg/L"},{"name":"PFPeS","valueText":"<0.004","unit":"µg/L"},{"name":"PFTA","valueText":"<0.008","unit":"µg/L"},{"name":"PFTrDA","valueText":"<0.007","unit":"µg/L"},{"name":"PFUnA","valueText":"<0.002","unit":"µg/L"}],"comparison":{"proposed":{"value":0.0005,"period":"annual_mean","official":false,"state":"inconclusive"},"sweden":{"value":0.004,"jurisdiction":"se"},"franceSum20":{"value":0.1,"jurisdiction":"fr"}}},"samples":[{"id":"810-123430-1","date":"2024-10-08","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["10071/10071"],"sum20":null,"pfas4":{"value":0.0131,"valueText":"0.0131","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"385a5641fc3dee76bc1f9fcfdf4a3fd0e789fd9be6393c141c0d76e07eca1573"},{"id":"810-104651-1","date":"2024-05-14","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["10071/10071"],"sum20":null,"pfas4":{"value":0.0132,"valueText":"0.0132","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"b3b7b960d9e15ae70f21d68b63236055c89d54a26c17f5228dfcf1bcd90eee8b"},{"id":"810-100147-1","date":"2024-04-09","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["06810/10001"],"sum20":null,"pfas4":{"value":null,"valueText":"<0.015","unit":"µg/L","nonDetect":true,"lowerBound":true,"qualifiers":[{"name":"PFOA","valueText":"<0.004","unit":"µg/L"},{"name":"PFOS","valueText":"<0.004","unit":"µg/L"},{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"7a3d2a72bc5fb47149ef373057e35b2a0ebb0f35723cd2732eb3456c9ee632da"},{"id":"810-100148-1","date":"2024-04-09","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["00042/11949"],"sum20":null,"pfas4":{"value":0.0067,"valueText":"0.0067","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFOS","valueText":"<0.004","unit":"µg/L"},{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"b3df88914d1ec8b9fcd6fe023e10c822e00faadac1780622c7516ad4b86d1909"},{"id":"810-100150-1","date":"2024-04-09","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["00009/1305"],"sum20":null,"pfas4":{"value":0.0117,"valueText":"0.0117","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"ea9f8808d7bf8262e2e36c3c93776e97f7ffc637de22ce75c528915db814e673"},{"id":"810-89127-1","date":"2023-12-27","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["00009/1305"],"sum20":null,"pfas4":{"value":0.013,"valueText":"0.013","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"32bd0704d3dc1eb1611a56238b927c24632210a01a6d38e6734001ec1f4b0f2a"},{"id":"810-81428-1","date":"2023-10-12","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["06810/10001"],"sum20":null,"pfas4":{"value":0.0161,"valueText":"0.0161","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"faf9c0c2bc7166b8507e13aae02a56918e048a2562cd4542a5b76c38191cfd87"},{"id":"810-81436-1","date":"2023-10-12","commune":"MA3056000","communeName":"CHELMSFORD WATER DISTRICT","sourceUrl":"https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule","networks":["00042/11949"],"sum20":null,"pfas4":{"value":0.0071,"valueText":"0.0071","unit":"µg/L","nonDetect":false,"lowerBound":true,"qualifiers":[{"name":"PFOS","valueText":"<0.004","unit":"µg/L"},{"name":"PFHxS","valueText":"<0.003","unit":"µg/L"},{"name":"PFNA","valueText":"<0.004","unit":"µg/L"}]},"revision":"4de953393a94533913ba4b87b69e831b6c159b8197c861818cbd52045019e043"}],"revision":"9fa3f46597d9468813ddc04cabba69c4d7ca8282fd9ceda5110abac5309aa6f0","us":{"pwsid":"MA3056000","state":"MA","systemType":"CWS","sizeClass":"L","sourceWater":["GW"],"counties":["Middlesex"],"zips":["01824"],"entryPoints":4,"samples":10,"detectedCompounds":["PFOA","PFOS","PFBS","PFHxA","PFPeA"],"treatment":["GAC"],"potentialSources":"No","pfoaMax":0.0089,"pfosMax":0.0072,"hazardIndex":null,"centroidSource":"sab"}}