I would not want those in my septic system, but they are probably relatively harmless at dilute levels recommended by Five Star. Even so, I just pitch them out on the driveway or patio and they flow into the grass. In winter it goes right into the yard.On this episode of Brew Strong Jamil and John Palmer cover properly cleaning your brewing equipment. To help tackle the topic, Jon Herskovits of Five Star Chemicals joins the discussion to add insight about the right chemicals for the right job and how they affect your brewing, equipment and the environment.
I've been using them with no problems and Jon from Five Star specifically addresses septic systems in this podcast.
Yes, I use them, as well, but especially as to PBW, I would avoid septic tank disposal, despite the claim that there is no harm at mfg. dilution levels. But I add helpful bacteria regularly to my system just to be sure. My septic tank guy recommends it so it doesn't require as frequent pumping as without.