At first I was using a few of these standard watering bottles:
They work fine but they need to be cleaned and filled daily at least, sometimes twice a day. The quail poop in them and make a mess out of them quickly. So I installed these cups:
The water just gravity feeds into the watering cups. I fill the bucket up as needed, which is about once a week (for 20+ quail). This was the best improvement that I’ve made to the cages yet. Cleaning out the birds watering bottles was time consuming and getting old.
I just got a 5 gallon pail, drilled a hole in the bottom and put a fitting in there with a rubber gasket on each side with plenty of silicone sealant. It hasn’t leaked yet. Use a fitting that will accept a ½” PVC threaded adapter that you can screw on to the fitting in the bucket and glue onto the ½” pipe. Installing a valve is a good idea in case you need to remove the bucket for cleaning, replacement, etc.
The quail don’t actually learn that they need to tap this lever for water to come out (they aren’t that smart). They reach in to get the last bit of water in the bottom of the cup and hit the lever in the process. This lets some water out, so the cups never go totally dry. You can also disassemble the cups if they get gunked up or if the little o-ring inside deteriorates and needs to be replaced.
Some quail keepers use nipple type waterers, but I thought that those would drip enough that they would make a mess in the manure pans and cause the manure to stink more.