Saturday, May 27, 2023


Can we use bottled water for the RV toilet in winter?

RV Doctor

Dear Gary,
This is our first winter with an RV. If we winterize our 5th wheel and then want to go camping in the cold weather, is it safe to use the black tank with bottled water only? Since the black tank hoses appear to be quite large it’s hard to believe they would freeze. Or are there smaller hoses somewhere in the black tank system that we can’t see that could freeze? We would be using bottled water only for any fresh water needs, so we wouldn’t disturb the anti-freeze in the rest of the system. Is our thinking right on this? —Barb

Dear Barb,
It is perfectly doable to use the black tank with bottled water if you choose that route. It’s also possible to use the complete fresh water system in the coach during the winter with some proper preparation. (See some tips in my post last week.) But typically it’s a full 3-inch drain from the toilet into the solid waste holding tank so just pouring bottled water into the toilet before and after each flush, you should be fine.

I’d add a little RV anti-freeze to the bottom of the holding tank just to keep it from freezing if you’ll be in extended below-freezing weather. And remember, you’re in an RV so you can always head south!


Read more from Gary Bunzer at the See Gary’s videos about RV repair and maintenance.




0 0 votes
Article Rating
Subscribe to comments
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Gene Bjerke
4 years ago

Since we winterize by hooking the pump input to a bottle of anti-freeze and pumping until the taps run pink, the few times we use the RV while winterized, we just leave the system set up and flush with anti-freeze. Just make sure you have a full-enough bottle in the system.

Brad Teubner
4 years ago

When cold out and the system is winterized, we use -20F windshield washer fluid to rinse the toilet. So far has worked to -5F with no issues.

Sign up for the

RVtravel Newsletter

Sign up and receive 3 FREE RV Checklists: Set-Up, Take-Down and Packing List.