[JRTJH]

You usually can't get an adjustable wrench on the drain by putting it along the drain sides, but if you approach it from the top of the drain plug (which is actually the front of the water heater if you're standing in front of it) you can usually get an adjustable wrench on the top of the plug and use a screwdriver in the hole on the other end of the wrench to turn it. The wrench will only turn about 1/8th turn, then you'll have to put it on the next "flats" on the drain plug. Keep doing that until it's loose enough to turn by hand and you're done.

Mine is 15/16th, but it was a lot easier to get a 8" crescent wrench on the top of the plug.

Don't forget, if it is the metal plug with or without an anode rod, when you put it back in, apply new teflon tape to the threads !!! Otherwise, it won't come out next year!!!!! This doesn't apply to the nylon plugs.