Understanding your personal PFAS exposure risk from drinking water has become much more accessible in recent years as federal and state agencies have published increasingly comprehensive contamination data, monitoring results, and interactive mapping tools. Knowing how to navigate these public resources empowers residents to make informed decisions about water testing and filtration before waiting for utility notification or media coverage of their local contamination.
Key Public Data Sources
EPA’s PFAS Analytic Tools (PAT)
The EPA maintains an online mapping and data portal (available at epa.gov/pfas/pfas-analytic-tools) that consolidates PFAS occurrence data from multiple sources, including UCMR 3 and UCMR 5 monitoring data (Unregulated Contaminant Monitoring Rule), known contaminated sites, and regulatory actions. The interactive map allows users to search by location for nearby PFAS contamination sites and water system monitoring data.
EPA’s Safe Drinking Water Information System (SDWIS)
SDWIS contains compliance data for all public water systems subject to EPA regulations. As PFAS regulations take effect under the 2024 NPDWR, water system compliance data will be publicly available through SDWIS, allowing consumers to look up their utility’s PFAS monitoring results directly.
Environmental Working Group’s Tap Water Database
EWG (ewg.org/tapwater) has compiled and mapped utility testing data from across the country, making PFAS results from thousands of utilities searchable by zip code. The database includes historical PFAS monitoring results even from systems that may not yet be subject to mandatory reporting, making it particularly useful for early identification of potential issues. EWG applies health-based thresholds that are often more conservative than regulatory MCLs, which should be understood when interpreting results.
State Environmental Agency Databases
Most state environmental agencies maintain their own PFAS contamination databases covering both public water systems and private well areas. These state databases often contain the most comprehensive and up-to-date information for their jurisdiction. Searching “[your state] PFAS contamination map” typically surfaces the relevant state agency resource.
PFAS-Affected Areas from Military Installations
The Department of Defense’s Environmental Restoration Program publishes data on military installations with PFAS contamination (sems.epa.gov for Superfund sites, and DoD’s own environmental portal). Communities near military bases should specifically check these resources, as AFFF contamination at military sites is widespread and may not be captured in utility monitoring data if affected residents use private wells.
Understanding Map Data Limitations
While these mapping resources are valuable, users should understand their limitations:
- Data lag: Published data typically reflects monitoring results from 1–3 years prior; current conditions may be higher or lower
- Coverage gaps: Private wells are generally not monitored or reported in public databases; rural residents using private wells must test their own water
- Compound coverage: Older monitoring data may cover only 6–14 PFAS compounds (UCMR 3); newer data covers 30+ compounds (UCMR 5); check which panel was used
- Detection limits: Results reported as “not detected” reflect the analytical detection limit of the specific method used, not necessarily zero PFAS
What to Do With Your Risk Assessment
If public mapping data suggests PFAS presence in your water supply or nearby contamination that could affect your water source:
- Request your water utility’s most recent PFAS monitoring results (required to be provided on request)
- Consider independent testing of your tap water through a certified laboratory for a current, comprehensive PFAS panel
- Evaluate water filtration options based on detected compounds and concentrations
- Register for utility PFAS notification programs if available in your area
Proactive use of public data resources enables households to assess their risk and implement protection before formal notification — particularly important given the health impacts of cumulative, ongoing PFAS exposure.