Bigger black tank

[Crows Nest]

We have a 21NE. Is it possible to install a larger black tank? We have a tote tank but a larger on-board tank would be helpful.

[Chamberman]

Anything is possible if you have the money and willingness to modify your trailer. However ETI supposedly looked into this a few years back when the info surfaced that the 19 gallon tank they were specing was really 13 gal in reality. They claimed at the time that they had investigated in a larger tank could not be installed. Of course that may be attempting to use off the shelf tanks of similar size, etc. it would certainly require significant modification to get a larger tank to fit.

[Selkirk]

Originally Posted by Chamberman

Anything is possible if you have the money and willingness to modify your trailer. However ETI supposedly looked into this a few years back when the info surfaced that the 19 gallon tank they were specing was really 13 gal in reality. They claimed at the time that they had investigated in a larger tank could not be installed. Of course that may be attempting to use off the shelf tanks of similar size, etc. it would certainly require significant modification to get a larger tank to fit.

Since the current black tank extends partially under driver's-side dinette bench, It might be possible to install a custom-size secondary tank under the bench immediately adjacent to the original, connected together by a short span of large-diameter sewer pipe at the base. However, that would require a lot of electrical components and wiring under the bench to be relocated. I also don't know how well such a set-up would drain nor how easy it would be to occasionally flush out.

I suspect that replacing the old tank with a larger one would require the entire bathroom floor pan to be removed.....which would be a massive (and probably impractical) project.

You could always look at retrofitting either a composting or incinerating toilet....which would eliminate the need for a black tank altogether.