active community water systems with complete monitoring
complete-monitoring systems meeting any April 2024 comparison
systems in the primary inferential cohort
primary-cohort systems meeting any comparison
Represented monitoring records by state
Counts use unique eligible systems and complete monitoring. They do not rank overall water quality or individual health risk.
“% meeting any comparison” is the share of active community water systems with complete monitoring that had at least one complete-set sampling location meeting an EPA January 2026 technical comparison. It is not a compliance determination.
Sort columns to inspect complete-monitoring denominators, any-comparison prevalence, or compound-specific system counts.
Select a state name for compound-specific system counts and a unique monitored-system directory.
Review the full methodology for system eligibility, sampling-location averages, threshold logic, and limitations.