All data displayed on YourWaterReport is sourced from publicly available government databases. We do not generate, sample, or certify any water quality data. Our role is aggregation, geographic linking, and presentation. Here is where the data comes from.

Water Quality Portal (WQP)

The Water Quality Portal is a cooperative service operated by the USGS, EPA, and USDA that integrates water quality data from over 400 federal, state, tribal, and local agencies. It contains hundreds of millions of groundwater monitoring records spanning decades. WQP is our primary source for county-level contaminant measurements.

USGS National Water Information System (NWIS)

The USGS NWIS provides groundwater level data, well construction data, and aquifer information for monitoring wells across the country. We use NWIS data to supplement WQP records and to provide aquifer context on county pages.

EPA ECHO

EPA ECHO (Enforcement and Compliance History Online) provides public water system compliance data and facility information. We use this to provide context on municipal water quality where relevant to private well owners nearby.

CDC Environmental Public Health Tracking

The CDC National Environmental Public Health Tracking Network provides county-level health statistics — including disease prevalence data that we reference on county pages where a documented link to specific well water contaminants exists in the scientific literature.

U.S. Census Bureau (American Community Survey)

We use ACS 5-year estimates for county-level housing age data, which serves as a proxy for lead risk from pre-1986 plumbing (lead solder was banned in 1986).

EPA TRI (Toxics Release Inventory)

The EPA Toxics Release Inventory tracks industrial facility releases of toxic chemicals. We use TRI data to flag counties with nearby industrial sources that may contribute to groundwater contamination.

EPA Superfund (CERCLIS)

EPA's Superfund site database is used to identify counties with active or legacy contaminated sites that may affect groundwater quality.

State agencies

For some states, we supplement federal data with state-specific groundwater monitoring programs. State environmental and health department data is used where it provides coverage not available in the federal databases.

For full details on how this data is processed and aggregated, see our Methodology page.