empty water tanks

Can any one tell me how to empty water tanks without using faucets

On Red Ranger, we use a portable wash down pump to pump the water from the tanks into the galley sink drain. We still have the original aluminum tanks, so we get lots of sediment in the tanks. Once we've cleared most of the water out with the wash down pump, I go after the sediment with the mini shop vac. Then I contort myself into various shapes to scrub down the inside of the tanks with vinegar and a long-handled dish brush and a rag. It's some kind fun, but I only do it once or twice a year.

If you find an easier solution, please let us know!