If you've ever had pigs, you know how hard it can be to keep their water trough clean. Heck, even if you've never had pigs I'm sure you know how much they love mud. Pigs + water = mud! I started out with a few shallow water pans for the pigs, and I'd have to fill them several times a day. As soon as I'd fill them, the pigs would flop over on them.
I got tired of having to refill them all the time, so we made a pig waterer. It cost us $5, since all it took was a barrel and a nipple. We already had the barrel (it was our chicken cooling barrel when we raised meat chickens). It was simple to make, we just cut a hole in the barrel and used Q-Bond (a heavy duty super-glue like material) to glue the nipple in place. It has held up beautifully.
Then we set the waterer outside of the pig pen and put the nipple through the fence. We elevated it so the nipple is almost a foot off the ground.
It took them a while to use it, so I left the old water pans in there
for a few weeks. They weren't figuring out how to use it, so when I was
home all day one weekend I took their water pans out and used
marshmallows to entice them to bite the nipple.
After about 20 minutes and 10 marshmallows (stuck on the end of the nipple), they finally figured it out. Actually, it was the littlest piglet who figured it out first. Once he got it, the others copied him. Now they always have fresh clean water, and I don't have to refill it multiple times a day!
I do still give them a mud hole though. You can't have pigs in these hot summers without giving them a wallow!