---
title: "Groundwater levels (OGC field-measurements)"
method: GET
path: "/api/v1/environment/usgs-water/gwlevels"
tags: ["Environment"]
---

# Groundwater levels (OGC field-measurements)

`GET /api/v1/environment/usgs-water/gwlevels`

Discrete field-measured groundwater levels. OGC-only: legacy `/nwis/gwlevels/` was frozen 2025-11-01 and redirects to the decommission notice as of 2026-02-01. Sugra sources this from the OGC `field-measurements` collection - the official replacement.

## Query parameters

- `site` string, required — USGS site number (groundwater wells are 15-digit).
- `start_date` string — Start date YYYY-MM-DD.
- `end_date` string — End date YYYY-MM-DD.
- `limit` integer — Maximum measurements to return.

## Response `200`

Discrete field-measured groundwater-level observations.

- EnvelopeUSGSWaterGwlevelsData
  - `data` USGSWaterGwlevelsData, required — Response for GET /gwlevels (OGC field-measurements, gwlevels replacement).
    - `measurements` USGSWaterFieldMeasurement[]
      - `site_id` string, nullable
      - `parameter_code` string, nullable
      - `parameter_name` string, nullable
      - `time` string, nullable
      - `value` number, nullable
      - `unit` string, nullable
      - `method` string, nullable
      - `approval_status` string, nullable
    - `count` integer
    - `api_version` string, required
    - `note` string, nullable
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

[API](https://skmtc.net/sugra/apis/sugra-api.md) · [All operations](https://skmtc.net/sugra/apis/sugra-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/sugra/sugra-api/versions/4e2740743eb4/schema)