I'd look at an obvious place first.
The area where the heating element(s) screws in the tank.
I would suspect that since you're shutting the electricity off, the area where the element(s) are located have "contracted" just enough to break the "seal" between the element and tank and you may have a seepage issue...
If you see the "tracks" of where the water is seeping out of the tank, turn off the electricity servicing the tank, turn off the tank's water supply, drain the tank, remove the element(s) and reapply whatever sealant they use when those elements are installed for the first time, reinsert the element(s), turn water supply back on and bleed the air out of the system while you're checking for leaks, hook the electric service back up, turn the electricity back on and be sure you haven't shorted anything out...now, you're golden.
Unless your water is so bad, your tank probably has another 5 years left on it, at least.
The only other place(s) your tank would leak (unless it has a "blow-out" spot forming) are the inlet/outlet points.
If it's leaking there, call SEARS/HOME DEPOT/WHEREEVER and get the latest/greatest and schedule delivery...the old one is out'a there!
Good luck!
