[droithomme]

Cl's in toilet cleaner. Dilute is not a problem.

Cu though is an aquatic herbicide (used to rid decorative ponds of all plant life including algae) and can mess up things.

> at the end of the day everything goes to a wastewater treatment plant

Some of these things, especially the photosensitive chemicals in particular ammonium dichromate will annihilate the wastewater treatment plant. Experienced this problem in an industrial context once, resulting in tens of millions of dollars in damages to taxpayers and a giant fiasco. As a result our privileges to use the municipal sewage system were withdrawn and we had to spend tens of millions in evaporation towers since no water could leave our facility ever again.