Instantaneous Values

This service lets you acquire near real-time water data from thousands of sites managed or monitored by the USGS across the country. Readings are usually made every 15 minutes and transmitted hourly.

Daily Values

Daily values are summarized data about our nation’s streams, spring, lakes and wells derived from regular time-series equipment at these sites. Daily daily available for USGS water sites include mean, median, maximum, minimum, and/or other derived values. Many sites have periods of record for a decade or more. This service allows you to find daily values for time-series sites, both current and historical, using a number of flexible filters.

Site Service

The USGS has information about millions of sites: locations where hydrologic (water) data is or has been collected. There are thousands of real-time alone. The site service allows you to find relevant sites of interest using a number of flexible filters, and provides key metadata about each site as well as optional information on the type of data collected at the site and the data collection period.


Retrieve daily, monthly or annual statistics for sites. Statistics are provided on approved data only for time-series sites. Statistics are available for any parameter on these sites with approved data. Statistics include mean, minimum, maximum, mean and various percentiles.

Groundwater Levels Service

You can use this service to retrieve historical manually-recorded groundwater levels from hydrologic sites served by the USGS. If you are looking to retrieve data for real-time or recent groundwater levels recorded with automated equipment on a regular basis, please use the instantaneous values web service.

General Questions

Questions that are most often asked that do not fall in any specific service topic.

Writing Fault Resistant Code

Questions that are most often asked that do not fall in any specific service topic.