---
title: "Groundwater and monitoring-well context (USGS Water Data)"
method: POST
path: "/api/locus_groundwater_context"
tags: ["groundwater", "water", "wells", "aquifer", "septic", "site", "usgs", "read-only", "free", "free"]
---

# Groundwater and monitoring-well context (USGS Water Data)

`POST /api/locus_groundwater_context`

## Request

- Base URL: `https://api.locus.report`
- URL: `https://api.locus.report/api/locus_groundwater_context`
- Auth: none required

Nearby USGS monitoring wells, aquifer codes, construction-depth distribution, and latest water level, from national USGS Water Data. For well-water buyer diligence. Distance bands only. Not domestic-well or drilling-depth, water presence, yield, potability, contamination, or cost prediction. No wells is not no groundwater.
Use this when you can call Locus free tools (REST tools/call or MCP).
Use locus-groundwater-context instead when your client can only call paid x402 routes; it returns the same records. Direct flat-body route for this one free resource; no API key, payment, or catalog wrapper. Return only the cited bounded evidence described here; this route never produces a paid brief or full report.

## Request body

- object
  - `address` string: Optional US street address or place; NC uses AddressNC first, other areas use the national geocoder fallback when latitude/longitude are not provided.
  - `latitude` number: Optional decimal latitude; provide with longitude to skip address geocoding.
  - `longitude` number: Optional decimal longitude; provide with latitude to skip address geocoding.
  - `radiusMeters` integer: Bounded radius around the subject point in meters; default 5000, minimum 500, maximum 25000.

## Response `200`

Free cited evidence response.

- object

## Other responses

- `400`: Invalid request body.
- `429`: Rate limited.

---

[API](https://skmtc.dev/locus/apis/locus-api.md) · [All operations](https://skmtc.dev/locus/apis/locus-api/llms.txt) · [OpenAPI document](https://skmtc.dev/locus/apis/locus-api/revisions/ba7786b74adb?raw)