Gray water lines: What diameter?

[Mex-Busnut]

Dear friends

I need your advice on what diametr of CPVC pipe to use from the kitchen sink, shower and bathroom sink to the gray water tank. Is 1.5-inch enough?

Thanks in advance!

[mikke60]

1.5 should be fine. you do not need cpvc,however. Pvc is fine.

[Mex-Busnut]

Thanks a million!

[luvrbus]

ABS works best for a RV fwiw

[robertglines1]

Just remember poo flows down hill.  goes for all plumbing.  even fresh water if you plan on draining from low point in winter.   Good luck Steve.    Bob

[Seayfam]

Clifford is right. ABS (black plastic) is designed for drain lines. It won't let things stick to it as bad, so over time you won't get all the build up.
Above all that, all your local building supply stores will have all ABS p-traps that you will need.

Sent from my GT-I9100 using Xparent Green Tapatalk 2

[Van]

1.5 ABS here

[chev49]

i use 1 1/2 also, but spa line (pvc) is flexible, very tough. It can be glued just like the other into the connectors.  I use it when i want a flexible connection, like between the floor and the tanks in the compartment. 
has anyone else done this? it works really well as a flexible joint, and actually could be used for most of the drain lines, but it is hard to keep straight.

i have a 3 inch diameter piece of it between the toilet flange and the black tank, and the 1 1/2 to the grey tanks.

i have also noticed when doing initial experiments on it, that it needs well glued, and the glue has to dry for 24 hrs for a good bond..which has me thinking the plastic is way softer than the normal pvc. i was a bit concerned about this when after making my bonding experiment, that i put 3 short screws in the connetion to hold it in place...
have had absolutely no trouble, and my tanks can move a bit if they have a big vibration..
I also put the rubber connectors which have a band on each end... between each tank run, and one on each side of the sewer hose drop...

[belfert]

Remember that Steve is in Mexico and he can't always get the stuff we take for granted here in the USA.  I'm surprised that Mexican plumbing pipe is not metric.  My bus was made in Mexico and some plastic pipe used for conduit is metric.

[Tom Y]

1.5 " seems like over kill to me. I ran 3/4 or 1" and have had no problems. I also made a common trap for all 3, K sink, B sink and shower.  Tom 

[belfert]

The standard for drain lines in a house is 1 1/2".  I see no reason to go smaller in a bus unless you absolutely don't have the space.  The extra cost is quite minimal.

[bevans6]

up here the standard drain lines for almost everything but commodes are 1.25".  You can hardly buy fittings for 1.5" for most stuff, except bathtubs.

Brian

[belfert]

up here the standard drain lines for almost everything but commodes are 1.25".  You can hardly buy fittings for 1.5" for most stuff, except bathtubs.

The interesting thing is the trap on my kitchen sink is 1 1/4", but it connects to ABS plumbing that is 1.5".  My house was built in 2001 to then current plumbing code.

I did some research with Google and it appear that in the USA at least that only a bathroom sink is allowed to have a 1 1/4" drain.  Others are supposed to be 1 1/2".  Using 1 1/2" plumbing allows more fixtures to share the same line per code.  Canada might be completely different.

[Bussman84]

I too went 1 1/2" ABS on all our drain lines and also on the tank vents.
       Billy

[mikke60]

FWIW . here in Mass. 2" is actually required for showerstalls. A bit of an overkill it seems. mike