We are trying to determine the cities in the US with the best drinking water. To help us figure out which cities have the best water and which cities have the worst water in the US we have used EPA data to generate a risk score for every city over 100,000 population. Our answer to the question – where is the best tap water in the US – is based on the below metrics. These metrics are an estimate we plan on continuing to refine, but provide some level of quantitative score regarding the best tap water in the US.

The “overall risk score” is our current metric to convert the EPA’s SDWA data into a single metric per city (higher is worse):

25 points for every unaddressed health violation
5 points for every health violation, 1 point for every nonhealth violation in last 10 years
25 points for every lead sample above action level, 5 point for every non-zero lead sample in last 10 years
25 points for every copper sample above action level, 5 point for every non-zero copper sample in last 10 years

Scores for all cities above 100k population.