Since lye is so basic and caustic, it can harm PVC piping. The chemical should not react with the surface of the PVC piping, but if used incorrectly at high concentrations, it could eat away at a crack or flaw in the piping, causing it to fail.

Does lye eat pipes?

Here’s the problem: Chemical drain cleaners, such as caustic cleaners (containing caustic soda or lye), are bad for your pipes and your health. Using one of these chemical cleaners to unclog your drain could cause more harm than good in the long run.

Is it safe to put lye down the drain?

Lye. … The pros of lye are that it’s effective against sticky clog-smears like what you find in kitchen sinks, as well as thick hair clogs in bathrooms. The solution is denser than water, so you can pour it right into standing water and it will sink.