I think this is just a warning from a concern, but I don't see how it could be a problem. If you pour the water down the toilet, don't you continue to flush the toilet several times a day every day? How can it reconstitute? Same thing with the sink. You wash your hands, do the dishes, wash again, no time for it to reconstitute before is flushed all the way down to the sewage or your septic system. I guess if you pour tons and tons of it, like if you were using it commercially, it may be a concern, but personal use every once in a while is not a big concern. I rather dump it down the sewage that out into the outdoors. I have been using this for years and never had a single problem with my pipes. Ten years I had a septic system and for the last year with sewage, and never had a clogged drain. My two cents.