USGS stream gauges

1. Modernized Water Data APIs supersede WaterServices; legacy WaterServices will be decommissioned in the first quarter of 2027; decommissioning may include intentional degradation and blackouts, not before August 2026 www.usgs.gov
2. New APIs at api.waterdata.usgs.gov with replacements for all WaterServices endpoints; Decommission Campaign 3 retires remaining NWISWeb pages and WaterServices, expected November 2026 through February 2027 waterdata.usgs.gov
3. OGC API landing page (title, description: automated sensors and manual data collection), OpenAPI and collections links api.waterdata.usgs.gov
4. Collections list: latest-continuous, continuous, latest-daily, daily, latest-field-measurements, field-measurements, channel-measurements, monitoring-locations, time-series-metadata, peaks and lookup tables api.waterdata.usgs.gov
5. OpenAPI: apiKey security schemes in header and query, key from the signup page gives higher rate limits; licence 'US Government work in the public domain' linking CC0 1.0; termsOfService links CC0 1.0 api.waterdata.usgs.gov
6. Docs base URL ogcapi/v1, datetime syntax (interval, '..', ISO duration P7D), parameter_code/statistic_id filters, any response property queryable, next-link pagination, f=json, approval status field api.waterdata.usgs.gov
7. Keys managed by api.data.gov, sent by email from the signup page; passed as api_key query parameter or X-Api-Key header; more requests per hour before 429; X-RateLimit-Limit/Remaining headers (example 1000) api.waterdata.usgs.gov
8. More than a few queries per hour needs an API key; legacy /iv maps to latest-continuous and continuous, /site to monitoring-locations, /measurements to field-measurements and channel-measurements api.waterdata.usgs.gov
9. Queryable properties of latest-continuous (monitoring_location_id, parameter_code, approval_status, qualifier, state_code, site_type_code, etc.) api.waterdata.usgs.gov
10. Live keyless test 2026-10-26: USGS-01646500 discharge 2960 ft^3/s at 03:50 UTC, Provisional, last_modified 03:57 UTC; no X-RateLimit headers on the keyless response api.waterdata.usgs.gov
11. Live keyless test 2026-10-26: bbox + parameter_code=00060 returned features with time, value, unit ft^3/s, approval_status Provisional, last_modified (USGS-01650800 at 04:45 UTC) api.waterdata.usgs.gov
12. Live keyless test 2026-10-26: monitoring-locations accepts bbox and site_type_code=ST; results include a USEPA site and horizontal positional accuracy/method fields api.waterdata.usgs.gov
13. Live checks 2026-10-26 by territory bbox: same-day readings in Puerto Rico, U.S. Virgin Islands, Guam, Northern Mariana Islands; American Samoa newest reading 2008 (example: Guam) api.waterdata.usgs.gov
14. Real-time streamflow typically recorded at 15-minute intervals, stored onsite, and transmitted to USGS offices once every hour depending on the relay technique www.usgs.gov
15. Provisional data statement: subject to revision; improbable telemetry values automatically screened until verified; may be inaccurate due to instrument malfunctions or site changes; substantial revisions possible after field inspections; no USGS/US Government liability waterdata.usgs.gov
16. USGS-authored data considered U.S. Public Domain; credit requested ('Credit: U.S. Geological Survey'); not all site content is public domain; copyrighted items need the holder's permission www.usgs.gov
17. NIMS cameras endpoint (live 2026-10-26): 1,394 cameras (1,152 not hidden) with camId, nwisId, ingest schedule (interval 2-60 min, mostly 60 or 15; 24/7 or daylight) and public S3 image directories api.waterdata.usgs.gov
18. NIMS listFiles (live 2026-10-26) returned newest image filenames for IL_Lick_Creek_near_Woodside (04:45 UTC); the 720 px JPEG downloaded from public S3 api.waterdata.usgs.gov
19. No first-party USGS MCP server in the official registry; third-party USGS water servers listed registry.modelcontextprotocol.io
20. WaterServices degradation schedule: 2 s delay on all requests from 2026-11-16, 10 s from 2027-01-11, 30 s from 2027-01-25, redirect to the blog about 24 h on 2027-01-27, 60 s from 2027-02-01, redirect about 48 h on 2027-02-15, decommissioned 2027-02-22; users must migrate to api.waterdata.usgs.gov (checked 2026-10-28) waterdata.usgs.gov
21. USGS Water Data Statistics API (beta): observationNormals and observationIntervals; computation_type percentile/median/mean/min/max, normal_type DOY/MOY, start_date/end_date MM-DD, repeatable monitoring_location_id and parameter_code, page_size default 1000 max 10000, next_token paging api.waterdata.usgs.gov
22. Live keyless test 2026-10-28: USGS-08167000 discharge day-of-year 10-28 percentiles of the daily mean p25 57.7, p50 104.0, p75 185.0 ft^3/s over 87 years (legacy nwis/stat the same day: 59 / 107 / 185 over 86 years, 1940-2025); browser CORS allowed api.waterdata.usgs.gov
23. Live keyless test 2026-10-28: latest-continuous accepts parameter_code=00060,00065 and properties= in one bbox request (CORS *); it also returns series whose last value is years old (e.g. a 2001 reading), so 'now' readings must be filtered by time api.waterdata.usgs.gov

About. U.S. Geological Survey network of automated stream gauges reporting gage height, discharge and other water parameters, served free through the modernized Water Data OGC API (api.waterdata.usgs.gov). It supersedes the legacy WaterServices APIs, which USGS will retire during its final decommission campaign (November 2026 to February 2027, completing in Q1 2027). About 1,400 USGS river cameras at gauge sites also publish still images every few minutes to every hour through the public NIMS API.

Price. No fee is charged. The API key is free (managed by api.data.gov, emailed on sign-up) and only raises rate limits. USGS says anyone making more than a few queries per hour needs a key. Keyless requests returned data on 2026-10-26.

Coverage. Only existing fixed gauges; you cannot request a new gauge. The monitoring-locations collection also includes non-USGS agency sites (e.g. a USEPA site in a Washington DC bbox query), not all of which have continuous data. Some sites are discontinued and return null values with a DISCONTINUED qualifier. Live checks on 2026-10-26 found same-day readings in Puerto Rico, the U.S. Virgin Islands, Guam and the Northern Mariana Islands; American Samoa's newest continuous reading was from 2008. River cameras: 1,394 listed in the NIMS API (1,152 not hidden) across most states plus Puerto Rico and Guam. Total gauge count not verified.

Timing. USGS: real-time streamflow is typically recorded every 15 minutes and transmitted to USGS once every hour.

Licence. The API's OpenAPI description gives its licence as 'US Government work in the public domain', linking to CC0 1.0. It also links CC0 as the terms of service. USGS says USGS-authored data are U.S. Public Domain and asks for credit (e.g. 'Credit: U.S. Geological Survey'). Not every item on USGS sites is public domain: some third-party images are copyrighted and need the holder's permission. Recent data are provisional and provided on the condition that neither USGS nor the U.S. Government is liable for damages. The terms do not mention AI training or resale. Licensing of non-USGS agency data in the API was not checked.