In the US, or my part of it, at least, automatic car washes have become continuous engineering projects, with ongoing optimization of capital expenses and operating expenses. It seems like they are constantly tweaking them. I'm sure they reuse water multiple times, and in so doing, reuse the heat. If significant waste water goes to the sewer, they must use counter-current heat-exchangers to recover the heat for new supply.
Recovering waste heat from the electric motors may make sense at some point, but I'm sure there are many optimizations with better ROI.