I use a 5 gallon bucket, gamma lid, horizontal nipples and a stock tank deicer for my heated waterer. I like to use horizontal nipples, because they keep your water clean 24/7 and should not freeze during the winter as long as you have a heat source at the bottom your waterer. If you use the horizontal nipples, drill an 11/32 hole and screw the nipple in leaving 2 -3 threads showing, do not screw them all the way in. When the deicer is not needed(after winter), I put a piece of tape over the rubber grommet to keep any dirt from getting inside the waterer. Also, under the waterer is a plastic planter saucer I got from Lowes and the bucket sits on a couple bricks to raise it up some. The nipples don't drip water, but when the chickens use it, some water can drip and get the bedding wet. This is the only heated waterer I use in the winter, I have a 14 gallon non heated horizontal nipple waterer inside the run, but take it out during winter.
To keep the waterer filled during winter, I carry a couple gallon milk jugs to the coop and pour the water through the 2 inch hole the grommet is in. I don't usually clean out the waterer during winter, because it stays clean inside. I have a piece of cardboard nailed to the coop wall, so they can't jump on top of the waterer and poop on the lid.
I bought these parts from Lowes, to put the cord through. I drilled a 2 inch hole for the computer grommet(on right) to sit in, then sliced the rubber grommet so I could put it around the cord.
250 Watt Stock tank deicer that I use
2 - 3 threads showing on the nipple threads.