defined in RCW 90.48 (the Washington State regulation)

I have yet to see a legal definition of "chemical" although I have worked in water pollution control for over 40 years

Whenever anyone assert that "chemicals" are a problem, I know that they have no idea what they are talking about. Unfortunately such people have votes, and many are in postions of power and/or influence.

A substance discharged to a waterway has to cause some change in the physical, chemical or bioligical characteristics of the watercourse before it can be considered polluting. I find it hard to see that soap form a boat washing would constitute pollution, unless a large amout of usightly suds are discharges, or a lot aof baots are being washed in confined waters.

Dihydrogen monoxide is a polluting substance when introduced to some environments, but only the ignorant would consider it a "chemical"