It says in BIG LETTERS on the packaging not to dispose of it in toilets, sinks, or any other sort of drainpipe. Of course, I've been having a terrible time training my husband not to throw their clumps of FUR down the toilet. Our new house has a septic tank. Do you know how long hair (or fur) takes to dissolve? And what happens when a septic tank backs up? It's not pretty. :-)