Drano Max Gel and other Drano products are made and rated safe to use in all types of plumbing systems including PVC pipe which is a very common material for drain lines today.
The chemicals used in Drano Max Gel and other Drano Products are very powerful and can easily clean clogs by dissolving the clog but will not harm your plumbing in any way.
Drano Max Gel is also safe for septic systems and Garbage Disposals too.