> unless you're capturing the runoff

And doing what with it, exactly?

Hell if I know.

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.

You can allow the liquid to evaporate off in an evaporation pond, or combine it with an absorbent gel. Then the solids can be put in trash.