There are many available,from manufacturers like Wix,Perma-Cool,Raycor,etc...they come with a filter base that mounts on the firewall or wherever you want it,that has a bleeder valve to let trapped air out,and the filter,which has a water drain petcock on it...Jegs & Summit sell the Perma-Cool ones for about 35 bucks....you can also find a similar filter on early 6.2's ,I put one on my '82 GMC and "deleted" the secondary filter under the intake that sucked to change...
My '85 Suburban has a Raycor filter on it,but I'm not too fond of it--it uses a plastic bottom that is transparent that looks easy to crack when water might freeze in it,and the filters for it are pretty pricey and usually have to be special ordered...
I'd prefer a filter unit like the GMC has better,but I'll leave it on for awhile,till I use up the filters that came with it...
I'm tempted to get one of the Perma-Cool filters for my gas powered vehicles,with todays ethanol gas your chances of getting water is a lot higher than ever before,in your gas,and a water separator is nice,you can drain off any water before it gets in the carb or injectors...I used to run my old truck on "used" gas from the junk cars at the junkyard with one of those filters,and rarely had any issues ,once in a while I'd have to replace the filter,but when gas was free,the 15 bucks for a filter wasn't a big deal....wish I could get free gas NOW!..