Killing Mildew behind walls
We had a water heater rupture in the basement a few years ago. The basement doesn't have any external leaks, so we think the constant musty smell in our basement is the result of water getting into the walls when the tank ruptured. Indeed, I had to remove a small piece of drywall last year, and saw mold growing on the base horizontal stud. We weren't in a position to replace the drywall (requires a permit here!), so I cleaned what I could and just patched the section I had to deal with. I assume the horizontal stud, which has finished drywall on both sides, has mold all the way along it.
Question: is there any way to deal with this without ripping out a strip of drywall along the entire base, tall enough to get my hands in and scrub the stud with bleach? For example, is there any spray that I could inject in small holes drilled between the vertical studs in the drywall? (That would save lots of patching, and not risk the wrath of the drywall police.)
P.S. We run a dehumidifier all the time.