SDcampowneroperator wrote:
You can leave the dump valves open all the time. You must use plenty of water to flush the solid wastes Fill the commode twice, flush twice. All freezing weather campers do it when their waste tanks or valves are susceptible to freezing.( did it for years)
Max, this is a case where something works well for you, and very well might be a disaster for the next guy. I get that it should be just fine if you literally "chase" the deposit with a few gallons of water, but it's a huge waste of water, and not SOP for most users. I know for a fact that more than a few RVers will end up with a real disaster if they decide that they can leave their black valve open, and others will be just fine. It is highly dependent on the configuration of your black tank, and how well it evacutes any solids deposited. Many tanks tend to pool waste in the bottom since they have a bowl shaped bottom, or have other design quirks. In that case, a cone of solids will accumulate and eventually block the tank. As some experienced members here will attest, breaking this mound apart can be an unpleasant and difficult task. I know several people who made this mistake as beginning RVers, and one guy who got a really good buy on a used TT, with the knowledge that the black tank was totally clogged. The previous owner, who used it with the valve open, chose to not pay a repair shop to remove, and attempt to clean the tank.
Our 40 gallon black tank takes about a week of full time use to fill, leaving the valve open and wasting a few hundred gallons of water to avoid a build-up isn't something I recommend on a regular basis.