p-trap

[druidwood]

If I only have a shower/kitchen sink going to a smaller grey water tank, any reason I need a p-trap if there are no sewage odors? Also rather than elaborate air intake vents like in a house, couldn't I just have a vent coming out of the tank, rather than going up through the roof? Idea is to put the tank under the shower/sink.

Also wondered about just having a hose drain at the grey tank, rather than the large mouthed type on most rvs. With a vent on top of the tank, wouldn't it drain pretty quickly out of a hose? Thinking of a 30 gallon grey tank.

I haven't seen any pictures that showed a clean out plug at the bottom of the tank, does one worry about hair or odd items getting into the tank and how to get them out?

Thank you.

[CaptSquid]

A P=Trap, while not a necessity on a single tank system, isn't going to hurt. But, you WILL need a vent for the tank. Try using a vent designed for island kitchen sinks. You won't have to penetrate the roof.

[druidwood]

Looks like that would be a Air Admittance Valve (AAV), which I hadn't heard of before. Thanks.

[2kool4skool]

Only once have I wished I had a trap in the grey system. I had flushed out the water heater which was smelling really strong of sulphur and forgot to drain the holding tank. The next time I entered the bus...... Whew.

[turf]

yep - tanks stink!!! any tank

try hepvo instead of a ptrap. waterless ptraps don't freeze and break

[PNW_Steve]

I would STRONGLY recommend a trap for your shower and sink drains. If you spend any time boondocking in warm weather your grey water will get pretty stinky.

I have lived, full time, for close to nine years in buses and 5th wheel. Trust me, you don't want to smell your grey water after it has aged a week in 80 degree weather.

[milkmania]

Originally Posted by PNW_Steve

I would STRONGLY recommend a trap for your shower and sink drains. If you spend any time boondocking in warm weather your grey water will get pretty stinky.

I have lived, full time, for close to nine years in buses and 5th wheel. Trust me, you don't want to smell your grey water after it has aged a week in 80 degree weather.

I STRONGLY concur!
Dead skin cells eventually start stinking. Then if you wash off an empty plate in the kitchen sink, you've given bacteria the food it needs to thrive.

Plus you'll have to contend with Pink Mold

The pink bacteria that builds up on the grout between your shower tiles is known scientifically as Serratia marcescens, and it feeds on fatty substances such as soap scum. Pink mold can cause urinary tract infections and infection of wounds

[chev49]

use p trap... the plumbing code was put in place for a reason. also, do automotive wiring correctly...

[dredman]

I can testify to both, living with and without P-trap. My first bus was my trial and error bus, and without p-trap it was fine till you emptied grey....unless you ever got under way. Then I guess there was a vacuum in the bus with any windows open, thus pulling a vacuum on the tank, thus pulling a LOVELY scent from the tank - and if you have a kitchen/food sink you WILL have odor in the tank. I put a p-trap in

[bigskypc50]

I have an AAV under my kitchen sink, the fixture furthest away from the tank and a P-Trap on every single fixture along with a 1/2" vent on my tank. No problems thus far.

[Stu & Filo. T]

I think you will find that grey tank will stink worse than the black,

[PNW_Steve]

Originally Posted by Stu & Filo. T

I think you will find that grey tank will stink worse than the black,

Stu,

I have to disagree. My s#!t does stink. Grey can be bad but, in warm weather, my black tank has been pretty foul.

I stopped at a truck stop in AZ several years ago that offered "free dump station". There was a semi parked in the way and I could not get to it.

The nice gent that worked there told me "no problem, just pull over that drain grate and dump. They go to the same sewer."

I pulled up and unleashed 86 gallons of black water. It overwhelmed the drain and made a 15' diameter puddle of black water. That is by far THE NASTIEST THING I HAVE EVER SMELLED IN MY LIFE!

Just my $0.02

[roach711]

Look at the Hepvo vent. It's a trap and vent in one with no water sitting in the trap which is nice when it comes time to winterize the bus.

Hepvo Waterless Valve

[chev49]

Originally Posted by PNW_Steve

Stu,

I have to disagree. My s#!t does stink. Grey can be bad but, in warm weather, my black tank has been pretty foul.

I stopped at a truck stop in AZ several years ago that offered "free dump station". There was a semi parked in the way and I could not get to it.

The nice gent that worked there told me "no problem, just pull over that drain grate and dump. They go to the same sewer."

I pulled up and unleashed 86 gallons of black water. It overwhelmed the drain and made a 15' diameter puddle of black water. That is by far THE NASTIEST THING I HAVE EVER SMELLED IN MY LIFE!

Just my $0.02

guess u wont try that one again... reminds me of the relative who asked me to look at his black tank on his bus which he attached with steel strap and drywall screws... and i told him to bolt it but he thought i was stupid... He then left salem oregon, and when his black tank was full on the freeway by bakersfield, the tank fell out on the freeway and burst... haha

[druidwood]

OK, general opinion seems to say do it. Appreciate the advice and will take it.

[family wagon]

Note on the air admittance valve: it's for admitting air. If the thing is working properly it won't let air out of the pipe. It's a check valve. In some situations a rush of water going down the pipe will create a vacuum behind it. If there's no place to let air in then it'll suck out the water from P-traps instead. AAV fixes that problem.

For venting a holding tank you need at least one vent that's open to the atmosphere, unimpeded by an AAV.