Most Canadian cities prohibit washing anything (car, bike, etc) outside with soap unless you're capturing the runoff. Even biodegradable soaps.
Car wash is the only legal way to use soap, for better or worse.
Car wash is the only legal way to use soap, for better or worse.
And doing what with it, exactly?
AFAIK the regulations were put into place to prevent untreated water from going into storm drains and into the water system, so presumably the cities are fine if you pour it down into the bathtub drain and let it go to the waste water treatment plants.
The trapped oil gets disposed of separately, the treated oil-free water goes to the sewer.