TapWatch | Drinking-Water Quality Risk

How to read this map

Hazard / signal: Drinking-water compliance signals
Exposure: Population served
Consequence / vulnerability: Community social vulnerability

Official/source values remain distinct from MitchellCo derived screening scores or estimates. Derived values are for prioritization and interpretation, not official warnings or predictions.

Where do drinking-water compliance signals overlap with large populations and social vulnerability?

Combines EPA Safe Drinking Water Act compliance screening with EPA public-water-system service areas and CDC social vulnerability. Non-official screening map: not a real-time tap-water safety determination. EPA notes SDWIS/ECHO violation data are reported quarterly and lag current conditions.

Data health

EPA ECHO / SDWIS complianceLoading

EPA service areasLoading

CDC county SVILoading

Oldest consequential input: waiting…

LayersDerived drinking-water concernEPA service-area outlinesCDC county SVI context

Concern scale

25–44: lower screening concern45–64: moderate65–79: elevated80–100: highest

Highest derived concern

#	Water system	Pop.	Score
Waiting for state data…

How the score works

Compliance signal, max 55
30 points when the system is returned by EPA ECHO's health-based-violation filter
+ min(15, 3 × quarters-with-violation in recent 3-year field), when available
+ min(10, remaining uncorrected violation points), when available

Exposure, max 25
min(25, 5 × log10(population served + 1))

Vulnerability, max 20
20 × CDC county overall SVI percentile rank

Total capped at 100. Missing ECHO detail fields contribute 0 rather than being guessed. The score is a MitchellCo screening index, not an EPA risk score or health advisory.

Interpretation & limitations

A Safe Drinking Water Act violation can reflect health-based standards, treatment-technique requirements, monitoring/reporting requirements, or other compliance categories. This map requests ECHO's health-based violation filter, but EPA's national data are not real time. Service-area polygons are incomplete and some are EPA-modeled rather than utility-supplied. A polygon means the system serves that geography; it does not mean every customer has identical water quality. County SVI is contextual vulnerability, not a water-quality measurement.

Sources, cadence & attribution

EPA ECHO Drinking Water System Search REST Services: SDWIS/Fed compliance and enforcement data; queried by selected state for active community water systems with the ECHO health-based violation filter. ECHO supports JSON/JSONP for web developers. Underlying drinking-water violation data are reported quarterly; this page rechecks no more than every 6 hours.

EPA Public Water System Service Areas v3: service-area geometry, PWSID, population served, verification/model metadata. Version 3 released March 17, 2026; layer data last edited May 29, 2026. Loaded once per state selection.

CDC/ATSDR Social Vulnerability Index 2022: county geometry and overall percentile rank; static 2022 vintage.

Map tiles © OpenStreetMap contributors. EPA and CDC source data retain their own attribution and terms.