You didn't make your question easy! Your thread is posted in "
TRAVEL TRAILER, 5th WHEEL & TRUCK CAMPER FORUMS > Travel Trailer Discussion" but when I used Google to search for "1801FB", the only identification of your RV you gave, I find it listed as a "Minnie Winnie" travel trailer.
According to the
owner's manual, pg. 7-3, the water pump is accessed under the bed.