Mold/Mildew under Linoleum

[rosky]

Hi Ya'll,

How common is it to find mold/mildew under linoleum flooring? And what's the best way to eliminate it?
I'm sure the wax seal on the toilet is leaking, and I'll fix that before going any further.
I also suspected a break in the copper (in my foundation) a couple of months ago and have since had that fixed...hired pro's to put PEX in throughout the whole house.
I figure the moisture under the linoleum is a combination of all of the above, and my first thought is just to let it dry out for a couple of days, then go over the exposed concrete with a heavy bleach solution, but any additional advice ya'll can throw out there would be appreciated.
Probably sounds elementary, but I'm just trying to cover all my bases before laying down tile in my daughters' bathroom.

I'll be back with many more dumb questions as this small hole in the wall has turned into an almost full on bathroom reno. But thanks in advance for the help.