[Sans Peur]

My 2000 41' open has both a raw water washdown and a live well pump in the stern. Both have their own thru hulls with seacocks and are wired from the breaker panel up by the helm so it was a factory option. On a couple of my old boats I used a single thruhull for both. They were T'd off above the seacock. The only problem I could see was possible cavitation if you used one of those bait well pumps that would allow backflow. The washdown pump could pull air back through the live well pump. I guess you could do a one way duck valve past the live well pump to stop it from doing that.