Tuesday, October 4, 2022


RV holding tank care

Dear Gary,
gary-736I think I’ve seen more words written about holding tank care and operation than any other single subject. Your discussion in Family Motor Coaching Magazine about cleaning black tanks was interesting and helpful. In the same issue, there was a description of an all-natural, microbial-based holding tank additive that, at least according to the maker, allows the microbes to digest waste such as proteins, oils, grease and paper, all the while preventing odor.

If this product does what it says, when I know my motorhome is going to be out of service for a couple of weeks, why wouldn’t I empty my black tank and then fill it up with water, dump in the appropriate amount of this product and let those microbes go to work? When I go back on the road, I empty the tank at my first stop and all the microbes and goop go down the drain, leaving me with a shiny, clean tank! There has to be something wrong with this concept but I don’t know what it is. —Rick C., Bradenton Beach, Fla.

Dear Rick,
There is absolutely nothing wrong with your concept, Rick. In fact, it is preferential. Bacteria-infused, enzyme-based tank additives can indeed help break down the solids and consume many of the odor-causing molecules at the root level. Keep in mind, however, it’s not truly designed to clean the holding tanks.

I’m not sure what brand of all-natural additive you saw, but the one I recommend is Pure Power Blue, by Valterra. While I’m not in favor of masking holding tank odors in hopes to not be distracted by them (there are other aftermarket products available that truly eliminate sewer odors in the RV), I am all for letting the enzymes do the dirty work (excuse the pun!). Masking the odor is considered a band-aid where live bacteria actually perform better in the long run.

If you’ve been using caustic chemicals or bleach or other bacteria-killing additives, it might be necessary to first “season” the holding tank to create a livable environment that encourages the good bacteria to be effective. So it may take a couple of flushings to be rid of the chemicals. Read the instructions on the container carefully. Most will come in liquid or solid form. Personally, I feel the liquid additive (at least with Pure Power Blue), works fastest. But you’re spot on with your idea.



Notify of

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

Inline Feedbacks
View all comments
6 years ago

I also squirt a good amount of Dawn into my black tank. I know it keeps my indicators clean.

6 years ago

How long does it take these products to break down waste? Paper? Human solids?

6 years ago

When my RV is not in use (not very often each year) I fill the black tank with fresh water and 2 cups of Rid-X (for septic tanks). Then dump the tank just before the next time I need to use it…