Professional carwashing is a "non-point source" of discharge that has the ability to capture these contaminants, normally in interceptor drains, so the contaminants can be removed before the water enters sanitary systems.
After initial injection, pigment is dispersed throughout a damaged layer down through the epidermis and upper dermis, in both of which the presence of foreign material activates the immune system's phagocytes to engulf the pigment particles. [wikipedia]
Roundscape Dev Team's goal for December is to finish Main Story and then do finishing touches and pregnancy system. Here is a pic for all the patient people out there.