Municipal water supply scores the trend in domestic water use per capita.
How is it scored?
For each county, average water use for every five year period was divided by the corresponding population size. A general linear model, which is a statistical model commonly used to detect trends, was run for each county to determine if per-person water use has increased or decreased (statistically significantly) over time. A score of 100% was assigned to counties where water use has decreased over time. A score of 100% was assigned to counties where water use has stayed the same. A score of 0% was assigned to counties where water use has increased over time. All scoring was based on statistical significance where p<0.05 is considered statistically significant. Region scores were the average of county scores within each region. For the overall score, population was used to weight region scores.