I can't think of why I need plumbing traps

[peter_nap]

The only discharge is greywater. It goes to a sand filter. There's no place to contain methane and traps are freeze problems. Can anyone think of a reason to use them?

[desdawg]

To pass inspection? If you ever want to put in a septic system or sell the home to someone who want to it will be a real pain to put them in later.

[PA-Builder]

If there is no plumbing inspection, I'd just plumb everything so that if any smell or bugs become a problem, it would be easy to install traps.  Just do some cutting of the PVC and put traps in.  PVC cuts very easy.  Real plumbers won't tell you to do this, but I agree with what you are saying.

[peter_nap]

Good points Des.....but, No inspection, Can't be sold because I put that in my will, no one will get it in my lifetime.

If I ever decide to put in a conventional septic system, I would only have two sinks and a shower to put them in.

I was a little concerned about bugs but screening at the outlet to the sand filter should take care of that.

[MountainDon]

I was a little concerned about bugs but screening at the outlet to the sand filter should take care of that.

If you go that route be certain to make the screening easy to get at because it will get clogged at some point.

Nice thing about a trap is it'll stop the diamond ring, whatever from going any further.

If you're going the non-standard, no inspection, no code route you might think about what I did on my RV. I removed the 2 sink traps, shower trap and routed them all to one trap just before the holding tank connection. In cold weather I only have to be concerned with that single trap.

Are you going to build in low point drains in the water supply system? I built an air valve into the RV to blow out the lines as well.

[glenn-k]

Even at that - Inspection or not -- the trap will prevent the stinky air in the pipe from getting into the house.

A trap could even prevent a potential family argument. :-?

"Oh Honey -- you have really bad breath tonight."

"It's not me  -- it's that pipe you didn't put a trap on -- its 30' long and it's the one with bad breath -- you're sleeping on the couch."

[peter_nap]

I don't know Glenn. I suppose there could be some odor from the grease trap but the idea of not having to remember to pour antifreeze down the thing is tempting.

In my 4" vent for the composting crapper, I have a vent fan that runs on a small dedicated solar panel and battery. There's plenty of capacity to run another from the 3 inch vent for the Bathroom sink and shower and the 2" for the Kitchen.
That would eliminate any possibility of odor.

[glenn-k]

If not too far to the grease trap and the pipe went under the surface it could function as a trap to stop air flow - maybe no smell problem especially if it is vented.  I have a gray water pipe system and now that I mention it I recall that I had to stuff paper towels into the washer drain opening that I didn't have a trap or vent on due to the smell of just the pipe.  Hmmmm -- gotta fix that some day -- this is a good point for do as I say - not as I do ---  OK -- voice of experience.  

[peter_nap]

It's not far to the grease filter. It is in a small chamber under the house that has a glass wall facing south. It has a cold frame vent to keep the summer temperatures down.  The composter is in there also. I guess the longest drain run to the grease filter is 10 feet for the kitchen with the sink and shower around 4 feet from floor level.

[desdawg]

Of all the chores involved in the building process I like plumbing the least. Crawling around in/under sink cabinets is not my idea of a good time. So I would be inclined to do it in the conventional manner to begin with while it is fairly simple to have access. The cost is minimal. JMO.

[peter_nap]

Cost isn't the issue Des.
Since this is a weekend place I would need to pour antifreeze in each drain every time we leave during the winter. If I forget and unfortunately I have reached the age where I do forget....a lot, I get to do one of my least favorite things. Replace broken pipes!

The water system has an electric valve built into the low point drain in the water system. When the power system is shut down, the drain opens on a timer for 30 minutes.

I can't do that with the traps.

[glenn-k]

You probably don't want to mess with this but why not tap the traps with a drill and pipe taps -maybe on the side to prevent cloggin - a little water wouldn't burst the trap --.and hook them to your drain valve also.  Pex would be easy to run to the drain and likely wouldn't break if froze anyway.

[peter_nap]

That would work Glenn...but it takes us back to the beginning of the circle. The real question is "Do I really need the traps".

This is an Ag. building. The codes don't apply, there is no permit needed and no inspections.
The issue of greywater was ...well....Grey and in fact I had to change the way water came in to stay under the somewhat conflicting health laws. Anyway..no health permit and no inspections.

This building will never be sold and in fact, this particular farm will not be sold in all likelihood.  It is set up so the taxes will be paid long after I'm dead and in order to sell it, my family would need unanimous approval among themselves and even then, the consent of a third party I appointed. Sometimes it pays to have a family full of lawyers.

Now, I try to follow the spirit of the codes. If it's not something that needs to be there and especially if it's detrimental...Like freezing....I want to bypass or modify it.

Since this is a contained greywater system, there is no methane to deal with. That is the primary reason for traps anyway.

Odor and insect intrusion is a concern but if I drain the traps, it;s the same as having no traps at all four and a half days a week.

It still looks to me like power venting the vents and leaving the traps out would be the best solution....unless...there really is another reason for having them.

[glenn kangiser]

I would say - your choice then -- The only reason for the traps that I know of is to prevent sewer gas and smells from entering the house.  

[skiwest]

The water system has an electric valve built into the low point drain in the water system. When the power system is shut down, the drain opens on a timer for 30 minutes.

I can't do that with the traps.

interesting, I'm going to face same thing,

but is it as much a problem in drain lines as they ae not full and room to expand in.

but could you put all drains to one trap, and on that trap have a trap bypass valve which would open on power outage?

or do it manually , valve to drain trap and another valve (large) to close the drains to the trap so that gases don't come back when the trap is bypassed?

[JRR]

It may be that the trap(s) can be installed below the frost depth.

[Jens]

You're not supposed to let those darned plumbers escape ofcourse!  Sorry, read the title, gotta be a smartass sometimes...ok, most of the time.

[glenn kangiser]

Good one, Jens.   I guess I must be slowing up to let that get by. :-/