There were two 3-way valves in my trailer. One is the fill/use valve the other is the winterization valve. Both from what I've seen are standard on most trailers neither are full flow. The problem is the rubber diverter that is used to change the direction of flow. When I bought my trailer I couldn't figure out why the freshwater flow was so poor. It wasn't until I tried to winterize that I figured it out. The lever that changes the direction of flow has 4 small weak prongs that protrude from the back and are supposed to turn the rubber diverter. What happens is the rubber diverter doesn't turn well and the prongs bend or break off and you end up blocking most of your flow. The dealer sells a brass winterization valve that you can use to replace the one close to the pump the other I had to get from a plumbing supply for about $15. Make sure that you get the full flow version. After I changer the fill/use diverter the water flow was huge improvement.