Well, this is the first time I’ve heard of a rain tax being imposed on my property, that’s measured by the square footage of my solid roof and my paved driveway! I already pay one of those water and sewer infrastructure fees on my property tax bill. This new tax will be in addition to the existing fee, as I understand it.
It might be new to your area; but the concept is decades old. We recently had a mini-scandal in Topeka, when somebody figured out the calculation for large Industrial sites was too low....and a guy in the city engineering dept. had to re-calculate a bunch of roof areas etc.
Part of my job description is to design detention ponds to help developers comply with stormwater rules....and in some cities get a discount on their stormwater fee. I’ve been doing this for fifteen years, and fees calculated on impervious area have been around for at least that long.