Q. When a unit is stored for a few months or longer, is it best to keep the holding-tank valves in an open or a closed position? Are they apt to dry out or crack if they’re left open? Is it best to leave some liquid in the holding tanks when the unit sits unused for some time?
— L.S., Colusa, California
A. To avoid plumbing-system damage when you reactivate your rig, Lee, it would be best to leave the tanks with the valves closed and a bit of potable RV antifreeze poured in the tanks. The antifreeze will take care of the valve parts during any rare cold snaps, and as you suggested, it will help keep the valve seals from drying out.
If your weather patterns preclude any deep-freezing temperatures, you could also use some of the holding-tank treatment chemicals that include valve-seal lubricants as part of their makeup.
Jeff Johnston, TL technical director, started RVing at age 6. During his more than 20 years as a writer/photographer, he has worked for Truckin’ and Four Wheeler magazines before joining TL’s technical staff in 1985. Johnston also has produced an award-winning travel video and TV commercials.