I live in a very wet area so I may be biased but water is very cheap as far as an operating costs goes.

Edit: also if you want to be a successful running a laundromat the water costs should be worked into your pricing so the cost of water is really a moot point. Its like saying the cost of eggs will bankrupt a groccery store, except a laundromat won’t be using any water a customer didn’t pay for unlike a store which might over order eggs.