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Open Data

Connecticut Public-Water Source Measurements by ZIP — Open Dataset

21,895 retained measurement groups, each tied to its public-water system, source programme, date, value, and unit, across 299 Connecticut ZIP associations.

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Important: ZIP association is retained legacy service-area metadata. It does not identify which system serves a household, and the dataset includes community, non-community, active, and inactive systems. Confirm the PWSID on a water bill or with the utility before applying a row to an address.

What's in it

One row per ZIP + PWSID + analyte + source + unit measurement group. Fields include the ZIP and city label, public-water system identity, system type and active state, population served, analyte, source programme, newest retained positive value and date, original unit, retained-row counts, and the exact archive, attribution, selection, and association states.

Selection rule: each row is the maximum positive value on the newest retained date within the exact PWSID, analyte, source, and unit grain. The retained archive has not been proved complete, so record counts are context—not detection rates.

No health or legal conclusion is embedded. This dataset contains no health threshold, EPA compliance verdict, safety claim, property condition, pet-safe number, or treatment recommendation. CheckYourTap's reviewed EWG/OEHHA-first health comparisons remain a separate, versioned evidence layer.

Coverage and verification

The capture evaluated 301 retained ZIP keys. It produced rows for 299, preserved one exact no-data response, and excluded one out-of-state ZIP. The files contain 94 distinct reported analyte names. Download the SHA-256 manifest to verify both formats.

Legacy download compatibility

The former 2,205-row aggregate files remain at their existing URLs so saved links do not break, but they are historical and are not a complete projection of the source measurement groups. Use the versioned files above for current analysis.

License & citation

Released under CC-BY 4.0 — free to use, including commercially, with attribution to CheckYourTap (checkyourtap.com). Suggested citation: “Connecticut ZIP-Associated Public-Water Source Measurements,” CheckYourTap (Valiant Energy Solutions), August 2026.

Want a readable ZIP-associated summary instead of raw records? Check your ZIP and confirm the listed PWSID before treating any result as relevant to a household.