Public Lake Hydrology Data API (v1)

Free, versioned, CORS-enabled REST API providing machine-readable lake water elevations, historical percentiles, and CSV downloads for developers, civic researchers, and outdoor app creators.

API Specification & Terms

Protocol: HTTPS REST JSON & CSV

Rate Limit: 60 requests / minute per IP

Attribution: Required backlink to waterlakelevel.com

GET /api/v1/lakes.json

Returns a list of all verified US lakes and reservoirs currently active in the WaterLakeLevel registry.

{
  "status": "success",
  "total": 21,
  "data": [
    {
      "slug": "lake-travis",
      "name": "Lake Travis",
      "state": "TX",
      "county": "Travis",
      "lat": 30.395,
      "lon": -97.907,
      "managing_agency": "Lower Colorado River Authority (LCRA)",
      "full_pool_ft": 681.0,
      "unit": "ft",
      "datum": "NGVD29"
    }
  ]
}

Test /api/v1/lakes.json →

GET /api/v1/lake/{slug}.json

Returns real-time elevation observations, climatology percentiles, and physical lake metadata for a single lake.

Test /api/v1/lake/lake-travis.json →

GET /api/v1/lake/{slug}/history.csv

Downloads historical daily observations and seasonal percentile curves in clean CSV format.

Download sample history.csv →