Question: What do I need to do to keep the freshwater system from getting nasty when we do not use the RV for a month or two during the warm months? Should I try to dry out the system or treat it with something to keep it from going bad?
Answer: The last time we stored our RV we went through the same thought process as you. We were going to be storing the RV for almost 5 months in Florida from April to September. We weighed the pros and cons of dry tank storage and wet tank storage for fresh water, as well as the grey and black tanks.
Here is what we did and why:
Fresh water system: Stored wet. We drained out the water system, removed internal water filter, refilled with sanitizing mixture of chlorine bleach and water. Then we ran all water faucets until we could smell the bleach. Closed all the faucets then added water to the fresh water tank until water flowed out of overfill drain.
We did this because it would have been nearly impossible to fully dry the fresh water system, since we live in the RV full time. Sanitizing the system was something that we could do just prior to storing the RV.
CAUTION: Make sure your water pump is turned off when you leave your RV in storage. You do not want to develop a leak and have your water pump run continuously until it runs out of water or power or burns out.
CAUTION: While we did not experience any downside to the sanitizing solution, nor had any problems when we flushed and drained the system when we returned, this solution may not work for everyone – so use this suggestion at your own risk.
Black and Grey water system: Stored wet. We drained and flushed the tanks, then refilled with fresh water and added twice the normal dose of usual chemicals we use to the full black and grey water tanks.
The thought was that we were not looking to sanitize – we were looking to have a chemical that would digest waste and solids.
CAUTION: To reemphasize, make sure your water pump is turned off when you leave your RV in storage. You do not want to develop a leak and have your water pump run continuously until it runs out of water or power or burns out.
We are happy to share what worked for us, noting that use of these suggestions is at your own risk. We always recommend that RVers consult their owner’s manual and/or seek guidance from the manufacturer to inquire about instructions or procedures specific to their own RV.