I agree - I am sure all of those things are wasting more water. But the water companies are being panned for not repairing leaks, car washes get closed during any drought, etc.
For window cleaners solely using wfp, isn't there a chance that there may be restrictions enforced in the future? No one will be paid what they should be worth then.

Being a newbie, I had forgotten that there is waste water produced too. From an environmental perspective, somebody is going to be looking at the industry soon, surely?
Just another thought, how much water do the trad cleaners use per day?