Combined 2 drain dumps into 1

[Indy Tim]

I watched a All About RVs YouTube post https://www.youtube.com/watch?v=BVPs8YGXKi4&t=296s and got inspired to combine my rear gray water discharge with the front gray and black. Tried out yesterday and works great. Also lets me combine both gray tanks by shutting the T-80 Valterra dump valve and opening both gray tank valves. I just need to do some foaming and it will be complete. I did have to reorient my fresh water valve (handle pointing to the rear)and remove my factory black hose container tube to make room for the 1 1/2" pipe. Next Mod is adding 5" fence post for black hose. I came off the rear gray water tank with a "T" thinking I would leave the rear drain attached if needed for some reason but it extended to low and I was afraid of it contacting the ground in extremes towing circumstances. I just used an expandable plug which will allow clean out if needed. Here is the list of items I used. Sorry for the the picture orientation, I couldn't get them rotated.

Valterra T-80 https://www.ebay.com/itm/Valterra-3-...53.m2749.l2648
Slip Flange https://www.etrailer.com/RV-Sewer-Ho...BoCExAQAvD_BwE
20ft of 1 1/2" ABS pipe
(1) 3" x 1 1/2" "T"
Several 90s
Pipe Hangers https://www.menards.com/main/electri...4430913904.htm

[John Mcgee]

I’m really interesting in doing this. Just not very handy

I watched a All About RVs YouTube post https://www.youtube.com/watch?v=BVPs8YGXKi4&t=296s and got inspired to combine my rear gray water discharge with the front gray and black. Tried out yesterday and works great. Also lets me combine both gray tanks by shutting the T-80 Valterra dump valve and opening both gray tank valves. I just need to do some foaming and it will be complete. I did have to reorient my fresh water valve (handle pointing to the rear)and remove my factory black hose container tube to make room for the 1 1/2" pipe. Next Mod is adding 5" fence post for black hose. I came off the rear gray water tank with a "T" thinking I would leave the rear drain attached if needed for some reason but it extended to low and I was afraid of it contacting the ground in extremes towing circumstances. I just used an expandable plug which will allow clean out if needed. Here is the list of items I used. Sorry for the the picture orientation, I couldn't get them rotated.

Valterra T-80 https://www.ebay.com/itm/Valterra-3-...53.m2749.l2648
Slip Flange https://www.etrailer.com/RV-Sewer-Ho...BoCExAQAvD_BwE
20ft of 1 1/2" ABS pipe
(1) 3" x 1 1/2" "T"
Several 90s
Pipe Hangers https://www.menards.com/main/electri...4430913904.htm

[Indy Tim]

I’m really interesting in doing this. Just not very handy

That is what I've done in this post.

[EddieK82]

What piece did you use that came out of the bottom with the cleanout? It has the red cap? I'm going to do this to my 320MKS next month.