EPA Sole Source Aquifer Screener — SDWA 1424(e) Review

Sole Source Aquifer (SSA) screener. Give it a list of coordinates and it runs a server-side point-in-polygon check against the EPA Sole Source Aquifers national layer and returns, for each point: whether it sits inside a designated Sole Source Aquifer, the aquifer name, the project-review-area type (Recharge Zone vs Streamflow Source Zone), the Federal Register citation of the designation, and the responsible EPA Region (with its contact link).

A hit means any project receiving federal financial assistance at that location is subject to EPA review under Safe Drinking Water Act section 1424(e) — the agency reviews the project to ensure it will not contaminate the aquifer so as to create a significant hazard to public health, because the aquifer is the area's sole or principal drinking-water source.

One clean, billable row per asset — even when the point is outside every SSA (a useful "clear" result).

Who it's for

• NEPA / environmental consultants — flag SSA review triggers early when scoping federally-funded projects, so 1424(e) coordination is not a surprise.
• Phase-I ESA / environmental due-diligence — add a definitive "is this site in a Sole Source Aquifer?" data point to a site assessment.
• Federally-funded infrastructure & development (transportation, housing, water, energy) — batch-screen a portfolio of sites for the SSA review requirement before applying for grants or loans.
• Water utilities & source-water protection — confirm which designated aquifer and review zone a facility or well site falls within.
• GIS & data teams / AI agents — enrich any coordinate list with authoritative SSA status without hosting the EPA polygon layer yourself.

Example input

{
  "assets": [
    { "lat": 41.68, "lon": -70.30, "label": "Cape Cod, MA" },
    { "lat": 32.7791, "lon": -96.8000, "label": "Downtown Dallas, TX" }
  ],
  "maxAssets": 500
}

The first point returns in_sole_source_aquifer: true, ssa_name: "Cape Cod Aquifer SSA", review_area_type: "Aquifer Project Review Area", federal_register_citation: "47 FR 30282 (1982)", epa_region: "Region 1", requires_swda_1424e_review: true. The second returns in_sole_source_aquifer: false (no SSA at that location).

Verified sample run

A real 6-site run (2026-07-21) returned 6 rows and 0 errors:

Asset	In SSA	Aquifer	SSA ID	1424(e) review
Cape Cod, MA	true	Cape Cod Aquifer SSA	SSA04	true
Long Island, NY	true	Nassau/Suffolk Counties Long Island SSA	SSA22	true
Spokane Valley, WA	true	Spokane Valley-Rathdrum Prairie Aquifer Area SSA	SSA71a	true
Tucson, AZ	true	Upper Santa Cruz & Avra Basin SSA	SSA61	true
Miami, FL	true	Biscayne Aquifer SSA	SSA34a	true
Downtown Dallas, TX (control)	false	null	null	false

The control point returned a clean, billable "clear" row rather than an error. This exact run is published as the actor's example task, so you can open it and re-run it as-is.

Output fields (one row per asset)

asset_label, asset_lat, asset_lon, in_sole_source_aquifer, requires_swda_1424e_review, ssa_name, ssa_id, review_area_type, federal_register_citation, epa_region, epa_region_number, epa_link, matched_aquifer_count, matched_aquifers, error, disclaimer, source_url, checked_at.

A single point can fall inside more than one SSA polygon — EPA ships some aquifers as separate Recharge Zone and Streamflow Source Zone polygons, and a point can intersect both. The flat row reports the primary (largest-area) matching polygon; every distinct match is also listed, deduped, in matched_aquifers, and matched_aquifer_count tells you how many zones apply.

Use as an MCP tool

This actor is callable by AI agents (Claude, Cursor, etc.) via mcp.apify.com. Its typed input (assets[]{lat,lon,label}) and field-level output descriptions make it a clean, chainable "is this coordinate in a Sole Source Aquifer, and does it trigger EPA 1424(e) review?" tool for siting, permitting and environmental-diligence agents.

FAQ

Is my site in a Sole Source Aquifer? Yes — pass its coordinate and read in_sole_source_aquifer, ssa_name and ssa_id.

Does my project need EPA review? requires_swda_1424e_review is true whenever the point is in an SSA. Projects receiving federal financial assistance in a designated Sole Source Aquifer area are subject to EPA review under Safe Drinking Water Act section 1424(e). Confirm the specifics with the EPA Regional Office in epa_link.

What is the difference between a recharge zone and a streamflow source zone? Both are parts of a designated Sole Source Aquifer's protection area. review_area_type reports which zone the point is in; a point inside both returns both in matched_aquifers.

Where does the designation come from? federal_register_citation gives the Federal Register notice (e.g. "47 FR 30282 (1982)") that designated the aquifer.

How current / authoritative is it? This is an informational SSA intersection screen based on the EPA national Sole Source Aquifers polygon layer (August 2019). It is not an official SSA determination or a substitute for EPA review. The authoritative source is the EPA Regional Office (see epa_link). Confirm the designation and review requirement before any siting, funding, permitting, or transaction decision.

Related screeners

This actor is part of a family of single-coordinate federal due-diligence screeners that all take the same assets[]{lat,lon,label} input shape, so you can run several over the same site list and join the results per site.

• Site Due Diligence Bundle — 15 federal overlays for one coordinate in a single call.
• EPA Contaminated Site Screener — nearest Superfund/NPL and contaminated sites, with a Phase I ESA flag.
• State Tank & Spill Registry Screener — UST/LUST tanks and state spill records near the site.
• EPA Impaired Waters 303(d) Screener — Clean Water Act 303(d) impaired waters near the site.
• Karst & Sinkhole Risk Screener — karst and sinkhole terrain, a common companion risk in carbonate aquifers.
• FEMA National Risk Index County Risk Profile — FEMA National Risk Index perils for the site's county and tract.

Source

EPA Sole Source Aquifers (August 2019) ArcGIS FeatureServer, layer 0: https://services.arcgis.com/cJ9YHowT8TU7DUyn/arcgis/rest/services/Sole_Source_Aquifers_August_2019/FeatureServer/0