I put ball valves on my last trailer ( Montego Bay ) and that worked great... I put ball valves on my new trailer , and they also work great...
1-fill the tank with the valve open
2-once it is full and water comes out the ball valve on the overflow ,close it
3- travel to campground
4-while setting up, open the valve.. Some water left in line will come out but that's it
5- don't touch out again till your next trip....
Not everyone has a full blown machine shop in thier garage, or the time to completely rebuild a perfectly good trailer when a quick fix will do the same...
