Impervious Surfaces and Your Tax Rate

This surface is "impervious." Rain can't get through it.

The following paragraph appeared this morning in a Roanoke daily newspaper story about the city budget:

The budget "includes implementation of the city’s Storm Water Utility, a system under which property owners will pay a fee based on the amount of impervious surface on their property. Beginning July 1, the fee will be 30 cents per 500 square feet of impervious surface per month. The fee will increase by 30 cents in each of the following two years."

Call me a fool, but I had no idea what an "impervious surface" was until I looked it up and found that it was, basically, pavement or ground covered by something harder than grass and dirt. I think a sharp editor might have explained that in the story.