I have asked how this worked in general, and now I believe I can confirm this is a "bug". I made a new character and this time around, I made shure when I picked the lead belly perk, that it worked. When I go to a sink, like in my room in Novac, brefore the perk the sink would say 5 rads. I got the perk, it said 2 rads then. Today I booted up the 360 loaded my game and now the sink says 5 rads again.

I also checked before I drank out of it, I had 116 rads. Took a sip, and now I have 121 rads. So you still get what ever it says.

So how come I am getting 5 rads drinking from a sink if this is not a bug?

i have the same problem...