Map Reveals Where the Cleanest Cities in the U.S. Are [Video]

The Portland-Vancouver-Hillsboro area is the cleanest metropolitan area in the United States, new research has shown.

A new study, conducted by Oxi Fresh, the carpet cleaning company, evaluated 35 major U.S. metro areas based on seven key indicators of cleanliness, assigning each city an overall grade from A+ to D.

The seven factors assessed include population density, rodent and cockroach prevalence, levels of vandalism and litter, air quality, and tap water quality, drawing from U.S. Census Bureau data and other government sources. Each city received a score across these criteria, which were then compiled into a final grade reflecting overall environmental cleanliness and public health standards to determine its ranking.

Eric Roy, lead scientist of the consumer product division at Culligan, a water systems treatment company, told Newsweekthat “cities in the top 10 [ranking of the study] generally reflect those with more pristine source water, newer infrastructure, and proactive efforts from …