Originally Posted by 40 to 332

I had the same question when I first purchased my magnetic drain plug a couple of years ago. Given that there was a fairly large gap between the threaded portion of the plug and the head of the plug, I elected to use both washers … with the solid washer placed on the plug first, followed by the copper crush washer. Never had an issue with leakage provided I snug down the plug. Trust this helps.