Trap on washing machine drain?

I'm in a brand new house and I'm wondering if my laundry drain was installed properly. It's raining outside and I am hearing water though the wall drain for the washing machine. I removed the washing machine flex drain pipe and there's no water coming from it, and there are no leaks by the valves or hoses.

I assume that I am hearing water coming into the drain from a vent. Should I be able to hear the water flowing through the drain? I can also feel some air flow through the drain, so I am guessing that there is no trap (I ran water through the drain to confirm the trap would be full if present). Should there be a trap?

ALL drains must be trapped. A toilet has a built in trap, but all others need to have a trap and be vented.

Not having a trap on that washing machine drain can cause souring of your clothes due to air movement through the cycles.

Since I can feel air being sucked into the drain and hear water running from the vent down the drain, is it safe to assume that there isn't a trap? Any quick way to tell without ripping out drywall?

If the home warranty has expired would the installation of a trap typically be done by the original plumber at no charge, since it was a code violation that didn't happen to get caught?

Thanks!

Yep, sounds like no trap. If you can prove in print the plumber installed the plumbing against code, he's liable.


Getting him to pay or do the work without spending a fine dime in court is another story altogether.

Should be no air movement between opening of fixture and the trap serving it.

to confirm whether there is a trap or not, you need to try a few things. First, do you know what a standpipe is? If not, search for info first. Then, stick something down that washer drain to see if there is water. Your standpipe will be quite long, and the trap is at the end of it.

david