Query California's public water system directory and compliance data via the state's CKAN open-data API (Drinking Water Watch dataset)
domain: data.ca.gov · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Locate the 'Drinking Water - Public Water System Information' dataset on data.ca.gov and identify its resource ID for the CKAN datastore
Call the CKAN datastore_search (or datastore_search_sql) API endpoint with the resource ID and desired filters/fields
Parse the returned JSON records containing PWS name, location, facility, source, and sample information sourced from the Water Boards' Drinking Water Watch portal
For SQL-style filtering/joins, use the datastore_search_sql endpoint, noting its documented 32,000-record result limit
Treat this as a state-specific reference implementation; other states publish similar PWS datasets on their own open-data portals with materially different schemas
Known gotchas
This is a periodically refreshed extract of the state's live Drinking Water Watch system, not a live pass-through; check the dataset's last-updated metadata before treating it as current
CKAN's SQL API caps results at 32,000 rows per query; larger pulls require pagination
Schema and field names are California-specific; this pattern does not generalize directly to other states without re-mapping columns
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