Wayne, welcome! Consider registering and joining our group.
What type pit do you have?
FWIW, I use sand in the water pan of my vertical smoker. The pan is lined with foil, then filled about 3/4 full of clean play sand. Then that's covered with foil to make a bowl to catch the drippings. In this case, the sand acts like a heat sink to help stabilize the temps. It'll run a little hotter than water, which is good for cold weather smoking. Just have to watch and not let the temps get too high, as it will take longer to bring the temp back down. Clean up is a breeze, BTW.
In the Chargriller, I use disposable aluminum pans under everything that takes a while to cook. These are started out with about an inch of water. The main purpose is to keep dripping from burning. A pan of water placed somewhere in the pit can also help better stabilize the temps. Although, this time of year, I'd use sand, instead.
It may just be me, but I've never noticed a difference in the meat done with/without a water filled pan.
Just my 2-cents.....
CharGriller Super Pro SFB
Sunbeam gas grill