Know your data sources.

North Dakota DEQ environmental data. ND DEQ AGOL + FracTracker mirror; no auth. - searchSpills (~5.4K) ⭐ Bakken-era oil + brine spills (FracTracker mirror, 2014) - searchStormwaterPermits (~2.9K) ⭐ Bakken well-pad construction permits by operator - searchGroundwaterMonitoring (~278), searchImpairedStreams (~34.8K Cat 5 = 303d), getServiceInfo upstream quirks: ND DEQ does NOT publish spills/USTs/air permits/abandoned pits as Feature Services — methods reframed against actual surface + FracTracker spills. Stormwater has NO COUNTY column — filter silently dropped, use bbox/near. Brine + crude oil spill upstream is the same dataset (deduped by Incident_ID when spillType:'all').

New Mexico Office of the State Engineer water-rights + groundwater data. AGOL Feature Services (owner: osegis), no auth. - searchWaterRights ⭐ — ~277,608 PODs filtered by county/owner/use/status/basin - getDeclaredGroundwaterBasin ⭐ — point-in-polygon basin lookup (39 polys, 161 with sub-basins) - searchPointsOfDiversion (alias), searchIrrigationDistricts (74 polys) - getServiceInfo quirks: county is 2-letter code (LE=Lea, ED=Eddy) — handler accepts both code + full name. POD geometry stored as UTM Zone 13N — outSR=4326 forces WGS84. use_ has 59 codes (OIL/OFM/SRO/MIN/INJ for O&G); status has 20 (PMT/LIC/EXP/CAN); pod_status separate (ACT/INC/PEN/PLG). 2 basin layers found — default 39-poly canonical, opt-in 161-poly with sub-basins.

Oklahoma Water Resources Board aquifers + floodplains + biological data. Native ArcGIS REST + AGOL Feature Services (owner: OWRBOnline), no auth. - searchAquifers ⭐ — 71 aquifer polys across 4 layers (Major/Minor × Bedrock/Alluvial) - getFloodplain ⭐ — point-in-polygon FEMA SFHA lookup (~23,539 polys) - searchStreamFishCounts (~10,749 obs), getServiceInfo quirks: Aquifers MapServer (csa.ou.edu) uses LOWERCASE field names (name/class/type) vs uppercase on AGOL. Floodplain is OWRB-published from FEMA NFHL — FLD_ZONE in X/AE/A/AO/AH; no name/county column. Stream Fish Counts has no county column — bbox/near is the geo filter; FISH_GROUP is taxonomic family.

California State Water Resources Control Board + DWR — drinking water systems + Bulletin 118 basins + stream gages. - searchDrinkingWaterSystems ⭐ ~5K SABL polygons. county UPPERCASE - searchGroundwaterBasins ⭐ ~515 DWR Bulletin 118 basin/subbasin polygons. NO county - searchStreamGages ~2.6K USGS+DWR+local. Filter hasFlow/hasStage/gageStatus upstream quirks: Multi-host — gispublic.waterboards.ca.gov (SWRCB native) for Drinking Water + StreamGages; utility.arcgis.com (DWR utility map) for Bulletin 118. SWRCB Drinking Water OWNER_TYPE_CODE has trailing space ('L ', 'P ' etc) — handler matches both forms. Bulletin 118 is published by DWR, exposed here for one-stop water context.

Texas Water Development Board groundwater data. Public ArcGIS REST FeatureServer, no auth. Layers: - sdr (~680k Submitted Driller's Reports — primary) - gwdb (~143k curated Groundwater Database sites with aquifers + water levels) - plugging (~242k Plugging Reports) - bracs (~89k brackish wells with geophysical logs) Owner names redacted by default; pass includeOwner: true only when explicitly requested. Counties returned in Title Case. Use bbox or near for spatial filters.