I have a washer drain line, 2 inch diameter stand pipe without a vent or trap. Should I be concerned; I haven't noticed any issues?

The stand pipe extends from a wall say 36 inches from the floor, does down; angles away from the foundation, then angles further down directly into the house's main drain line. I see the drain line (which is perpendicular to the washing line, go down under the footing toward the street.

I am interesting in remodeling and any such efforts should be done right within reason of good practices in plumbing. For example, is there any benefit of implementing a trap along this side branch without a vent?

Thank you,

Alpac... no trap?

Cover/plug that drain line right away.. ok? You just told me that you have a direct open line to the sewer main drain with no trap... that is a bad thing!

Are you sure this pipe connects into the main sewer drain line? It does not drain into a pipe that heads underground or underslab..

If it connects into main drain and you can follow pipe from start to end at main drain and there is no trap, then like I said, cap the line for now and let us know.

All waste lines connected to main sewer drain line in any way require a trap AND a vent. We are glad to guide you through information if you want! Mark

Maybe by using 'main' line I unintentionally misled...

I said house main line and that refers to a 6 inch (or so diameter) ABS pipe. I can see a 4 inch soil waste line (from a toilet) that goes into this "house main line".

This "house main line" is slanted on a continuous grade and does go under a garage slab, no doubt headed toward the street.

A picture or two would be a great help.

OK... my guess is three inch pipe to toilet and 4 inch (ABS) main drain line (looks like 5" or so)...but that is not really important...

What is, is that you have an untrapped and unvented washing machine drain line. That needs to be corrected.

How far from the main drain line is the washing machine? Can you find any FUTURE vents in basement (usually capped 2"(looks like 3" actual measure))?
Any vents from basement fixtures.. May be able to connect washing machine vent here.

And... you will need to add a ptrap.

Get back to us... Mark
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I attached a diagram of house without a vent / trap for Washing Machine drain line.

If you see the PNG formated diagram, you'll see heavy black line. Lets call that the house main line (or service line). That line I would believe is attached to a municipality street line.
From this large line, laying on a ground 4 feet below a house sub-floor.

There is a branch, that stretches 8 feet to an external wall. That wall is where the laundry room (orange) is located with a washing machine drain. It is 2 inches in diameter and slopes into the house main line.

There is a WC connection "in front of" as waste water runs. (That is a powder room (pink). All WC (except my WM line) have vents through the room (lead pipes) and traps.

Could there be a whole house trap that keeps sewer gases at bay?

Alpac:

You know there could be a house trap in floor... but does not matter, still would be getting sewer gas from your own home flowing into the house... that is still illegal and unhealthy.

They determined that house traps were not doing enough to protect the health of the public years ago and switched over to individual traps for all fixtures instead of whole house type.

I would install a 2" ptrap and an 1.5 " air admittance valve (AAV) at the washing machine. The standpipe out the ptrap should be 30 inches and the AAV should be within say 5 feet or less of the trap.

AAVs are not allowed everywhere... but they are sold everywhere (see pics.) and real easy to install. This vent needs to install so that it terminates a foot or two above the ptrap... I usually bring mine to same height as the standpipe.

So, trap the pipe, stub up standpipe 30", install a 2 x 1.5" tee fitting inline within 5 feet or less for the vent and then stub the vent up using an 1.5" female adapter to screw the vent into (pipe dope threads on AAV). That should fix this 100%.

Let me know your thoughts... Mark

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