Keeping up with keeping the waterers filled in the desert heat can be stressful. It's a constant worry that the birds will run out of water on a hot day when I'm not home. And filling waters for 18 runs of birds takes up quite a bit of time every day. But every automatic system I have researched is either too small, too expensive, or came with bad reviews from people I personally know that have used them.
And then I went over to a very dear friends house (who I have properly enabled into becoming a chicken keeper) and saw what her husband had designed after they came home from a weekend away to find that the person caring for their birds had let the waterers run dry in the middle of the summer heat. It was simply an extension off their drip system for their backyard plants.
I ran the idea past the husband (just to check and see if he thought I was crazy) and we came up with a plan. We already had a bunch of left over parts to our drip system and a water faucet right in the middle of one of the runs. Our only expense was some extra tubing (we got a lot extra in case we want to put more around the yard for trees and plants) and dog water dishes. Total cost around $70.
We ran the tubing along the fencing in the runs, put the water dishes up on bricks we already had and put a little drip tube into each bowl.
We also used an automatic battery operated timer from the garden and set it to come on for a few minutes every few hours throughout the day. Right now it is set for 15 minutes every 4 hours, but we may need to adjust that as we see how it works.