Merged Black and Grey Dump Points on my 23G

[74barrio]

For some reason Grand Design created separate dump points for the black and grey tanks on the 23G even though they outlet practically side by side. As someone who mostly boondocks and needs to dump at public dump stations, this setup was unacceptable. So I went to the local hardware store, bought a 3" elbow, a T swoop connection (not sure what to call that), and 2' of 3" ABS pipe just to make sure I had enough. Here are some before and after pictures (that's all fresh water on the ground since the trailer hasn't been put into use yet...way nicer to work on these when brand new). I also added a gate valve on the grey line as an extra level of protection so waste from the black tank couldn't go up the grey line inadvertently when dumping. This also lets me equalize the grey tanks for extra storage since i won't use the kitchen faucet as much as the bathroom shower/sink.

I've ordered a twist on Valterra gate valve to install at the end for one last level of security. Even with the drop at the angle needed to connect these drain lines there is still plenty of ground clearance.

[Country Campers]

Very nice job, thanks for sharing.

Brian

[Cate&Rob]

Nicely done, Dan. I am sure that other 23G owners will be following your lead. Maybe even the factory will take notice.

Rob

[Cate&Rob]

74barrio
Hi Dan,

I took your idea to the folks at Grand Design and learned that the reason for the two terminations is because there is an RV code that prevents the RV manufacturer from combining them if each grey tank is not vented through the roof and in the 21G and 23G both of these floor plans use a sidewall vent on one or more of the grey tanks.

Just FYI . . .
Rob

[74barrio]

Cate&Rob

Hi Rob,
Thanks for reaching out to Grand Design and getting that information. It looks like a code technicality rather than there being an actual problem if you tie them together as I have. At least I'm hoping that is the case as I can't see how what I've done would impact venting especially since I didn't change how the existing grey and black tank valves operate.

Dan

[Cate&Rob]

74barrio
Hi Dan,

The RV manufacturers follow a building code set by their own industry, the RVIA (Recreational Vehicle Industry Association). This code is a blend of residential and towable trailer requirements . . . and, quite honestly, some times does not make sense to those of us maintaining and modifying our trailers. You obviously understand how to use the changes that you have made. You might even wonder if Grand Design had this in mind when the placed the two outlets beside each other but could not link them because of their building code. But, that's just supposition on my part . . . certainly nothing endorsed by the manufacturer. I still like how you have modified your drain system and would do the same if this were my trailer. Those following this forum for a while will know that there are not many things on my RV that I have not modified from original, in some way .

Rob