I have made several version of these waterers:
I have a 5-gallon bucket version that I use in the summer that has 3/4" pvc coming out of the bottom of the bucket, to an elbow, to another piece of 3/4" pvc that is 4 feet long. I have 4 nipples on that piece of pvc. The pvc is black, so the nipples stand out, and the chicks took to it immediately.
I have another 5-gallon bucket version with three nipples in the bottom of the bucket that I use in the winter. It seems to me that using an orange bucket like you get at home depot didn't work very well for this due to the orange color of the bucket and the red color of the nipples was not sufficiently different, and the chicks didn't seem like they caught on as well, almost like they couldn't see the red nipples up against the orange of the bottom of the bucket. I changed to a white bucket, and they went for it instantly. In this winter bucket I put a bucket heater, and the water won't freeze. However, I've noticed that when it gets super cold (below 10 degrees) any remaining drops of water within the nipples will freeze, even while the water inside the bucket is not frozen. Above 10 degrees outside, the nipples don't seem to freeze.
In both of my bucket versions I have a bulkhead cut into the lid so that I can pour water in/out of the bucket or add some ACV or vitamins without taking the lid off.
I also have several other small versions that are made with plastic bottles (e.g. 1 liter water bottles, 2 quart orange juice jug, etc). These all have one nipple in the bottom of them, and I use these in my small coop that has younger chicks in it, and on the inside of my primary coop during the winter. By having several of them, I can swap them out in the morning and in the evening once they freeze up.
As others have said, use some plumbers' teflon tape around the threads of the nipples, regardless of whether you're screwing them in the pcv, the bottom of a bucket, or into a small plastic jug. I also suggest to also use some silicone. I've never experienced any leaks, even after many freeze and thaw cycles of my small waterers.