Designing Kitchens and Bathrooms - replacing carpet in bathroom

I am replacing the carpet in my bathroom with tile. When I pulled up the carpet, the subfloor around the tub and toilet were black with mildew about 1 to 2 inches out. Water stains were further out, up to 1 foot. I am planning on putting down vinyl tile (self-sticking). Is there anything I need to do about the mildewed subfloor? And do I need to put down a waterproofing substance before I lay down the tile?

these days mold and mildew are a hot issue - see Ed mcmahons lawsuit against his insurance company, if I was you I would try to remove the subfloor in the offending areas. You can do this with a circular saw set to the proper depth (so not to hit rafters) and replace with new. This is a little tricky but can be done. Nails will tell you where the rafters are but be careful. An alternative is to put bleach on it and try to dry it out

Thank you for your quick reply, I have one more question. If I go the bleach route, do I need to put a waterproof substance down before I lay the tile?

you need to get the subfloor dry as possible- follow instructions for the vinyl tile as far as whether you need something between the subfloor and the vinyl. It should list recommended subfloors. Please note bleach may not kill all the mold etc. Seriously look at the recent news about mold and mildew - I don't want to alarm you but it is best to be informed