The washing machine has a vent line that goes through the roof. I have an island kitchen sink about 12 feet away from the washing machine. It has an inline vent installed under the sink. For quite a while when the washing machine goes into a spin cycle at the end of the wash cycle and again at the end of the rinse cycle before it finishes the wash. When the washing machine spins it causes the kitchen sink drain to burp or something and all the water leaves the kitchen sink trap and I get a sewage odor. If I take off the inline vent it works OK. I had a plumber but he told me the drain lines were clear and that it was caused by my choice of and the amount of my laundry detergent. That is not the case but hard to argue with someone who thinks he knows what the problem is. Does the inline vent need to be replaced or is it another problem? Thank you.

Quote:

---

Originally Posted by jayrwv

The washing machine has a vent line that goes through the roof. I have an island kitchen sink about 12 feet away from the washing machine. It has an inline vent installed under the sink. For quite a while when the washing machine goes into a spin cycle at the end of the wash cycle and again at the end of the rinse cycle before it finishes the wash. When the washing machine spins it causes the kitchen sink drain to burp or something and all the water leaves the kitchen sink trap and I get a sewage odor. If I take off the inline vent it works ok. I had a plumber but he told me the drain lines were clear and that it was caused by my choice of and the amount of my laundry detergent. That is not the case but hard to argue with someone who thinks he knows what the problem is. Does the inline vent need to be replaced or is it another problem? Thank you.

---

Good morning Jay,

First off get another plumber. You know more about plumbing then he does.
By In line vent do you mean a island loop vent or a spring loaded mechanical vent? I'm assuming it's the latter. Your problem's caused by a faulty vent, and apparently two failty vents. Let me explain what's happening. The washer and the sink are on the same drain line. When the washer discharges it does so with great volume and pressure that sets up a vacuum that should be vented by the vent that goes to the roof. If that's clogged it attempts to wet vent through the sink. If that vents blocked also the only air it can get at to vent is through the sink trap after the water seal is sucked out. So what do we have?
We have two vents that are not doing their job. The only reason the sink drains without a problem is because it doesn't set up as much vacuum draining as the washer does.
The solution as I see it? Snake and clear the washer vent and replace the island vent.
You were right on target with your analysis of the problem. I hope you didn't have to pay for the plumbers unprofessional opinion. The sink "gurgle" should have been a dead giveaway and your guy missed it.
Good luck, Tom

You made my day, Tom. Oh, I had to pay for the call. Unbelievable. But I learned a great lesson. I am on the way to get a new inline vent. I really appreciate your help. I should have come here first. Such is life. Jay