Polygon service-area boundaries for community public water systems (CWS) in the United States — version 3 (March 2026) of the U.S. EPA Office of Research and Development's Service Area Boundary (SAB) dataset, reprocessed into cloud-native formats.
Model_Method column is empty for authoritative boundaries.The full v3 release also contains a T_NTNC layer (transient + non-transient non-community water systems — schools, campgrounds, gas stations, etc., ~77k features). Only the CWS layer is published here; T_NTNC may be added later.
The raw EPA zip (with documentation PDF and census crosswalk tables) is preserved at raw/PWS_Boundaries_Latest.zip.
See the STAC collection for the full data dictionary including values for coded columns and per-feature aggregation warnings on the hex asset.
H3 hex parquet is hive-partitioned by h0. Always include an h0 filter when querying a region — otherwise you scan all 122 partitions.
The SELECT DISTINCT cws.PWSID, ... step is essential — Population_Served_Count is repeated on every hex row a service area covers. See the hex asset's table:columns description for the full duplication caveat.
Shape_Area and Shape_Length are carried through from the source dataset in the original CRS units; they are not recomputed after reprojection. For accurate area, compute from the WGS84 geometry or use the H3 hex count.cng-datasets on NRP Nautilus.Model_Method | string | `` (authoritative) / Random Forest / Decision Tree / Parcel / OSM. Empty = highest confidence. |