* System scores are only calculated for active EPA systems; inactive and non-EPA (state regulated) systems are not included here. See list of system classification types for system type definitions.
† See list of specific service area types included in these categories.
‡ See explanation of priority non-compliers.
Calculation of System Scores
The system score is based on all unaddressed violations for monitoring periods ending within the last five years; unaddressed violations are those that have not been returned to compliance (RTC'd) and are not under formal enforcement. Violations for monitoring periods ending more than five years ago and those that have been addressed are not counted in the system score. For each water system, a system score is calculated using this formula:
System Score = Sum (S1, S2, S3, ...) + n
where S represents the points for each unaddressed violation and n
represents the number of years that the oldest violation has been unaddressed, from 0 to 5 years. Water systems with system scores of 11 and higher are considered a higher priority for enforcement.
Visit About System Scores for more information on system scores and how they are calculated, including the point values of specific violations.