The pump in my B1700 on the floor, the tank is underneath, and the maximum height the pump needs to draw is about 20 cm (8") - which has not been a problem at all for our pump, which looks original to the 1979 trailer.
Like Benny, I can understand that there may be reasons to put the pump under the floor, but I would rather have it clean and dry inside, even with the noise. Someday, I may even understand why it was mounted under the gaucho, instead of the obvious location under the sink...
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.