I usually don't like using thread tape on male plastic threads to metal, just some pipe joint compound. Just tighten it up good and snug, not tighten the heck out of it, and make sure it isn't cross threaded. I've seen leaks myself where thread tape was used in plastic to metal connections.--TheCapt.

I agree captain. Usually where that joint is, is a hassle to get disassembled and fixed once the job is done. Over the years I've had some that never leak with tape and I've had some that no matter what I did, it would leak when using tape. A little dope properly applied and snugged in and forget about it. I'm convinced water has eyes and reasoning power and it will find a way to get out if it can.