Terminology!! Our 2004 Tioga has a plastic spigot for emptying the fresh water tank just behind the driver side door. The "low point drain valves" are located behind a panel on the outside of the bathroom wall, but they are hard to reach and hard to turn. I had to get access through a hole in the wall, behind the converter charger, under the rear dinette seat. If you don't shut those #%* valves completely, your water pump will cycle or continue to run. I vowed to never mess with the "low point drain valves" again when sanitizing the fresh water system. Luckily we don't have to use and purge anti-freeze solution here in southern CA.