---
title: "Soil context & site constraints (USDA SSURGO): septic, foundation, drainage, shrink-swell"
method: POST
path: "/api/locus_soil_context"
tags: ["soil", "ssurgo", "septic", "foundation", "drainage", "site", "read-only", "free", "free"]
---

# Soil context & site constraints (USDA SSURGO): septic, foundation, drainage, shrink-swell

`POST /api/locus_soil_context`

## Request

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

Returns USDA NRCS SSURGO map-unit ratings at a point: dwellings with or without basements, septic-field, and shallow-excavation limits, plus drainage, hydric rating, slope, shrink-swell, and water-table and bedrock depths. For agents. Not a perc test, permit, or buildability finding. Urban points often return out_of_coverage.
Use this when you can call Locus free tools (REST tools/call or MCP).
Use locus-soil-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.

## 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)