Lets talk about gray water!

So - where is everyone? Lets talk about gray water. Our system is working fine these days except for the bear that bit the end of one water pipe! He did not break the line but must have smelled some tuna or salmon after we washed up dishes. I am wondering if we should put a few drops of peppermint essential oil down the gray water line after a dish washing that involves fish? Anyone else have animals bother the gray water lines?