I live in a single story house which is 5 years old -

I get a strong sewer smell in the house especially in summer when there are moderately high winds.

Also, the water in the toilet bowls moves when its windy.

I've changed the wax seals on both toilets.

I've even had a smoke test from the main sewer line and there were no leaks!!

I was wondering if putting vent pipe caps on would help?

Thanks for any help

Geoffrey:)

Best guess. I hope someone has better ideas.

The house may be too tight. The air pressure outside is much greater than the pressure inside.

Can you comment on how well the house is insulated against air infiltration? What type of heating system? Fireplace? Does the smell happen when a door or window is open?

Is there anything about the location of the pipes and nearby roof slopes that could divert winds into the roof vents?

Gelsus - One thing you can try is to put a45 degree fitting with about 12"to 18" piece of pvcand another 45 degree turn them in the oppsit way that the wind comes from. You can't put caps on the vents, Make sure that all drain traps have water in them all the time ,even if you have to turn the water on in the second bathroom sink if you have one . Kiss may be on to something but in the summer with the a/c on and blowing there should not be very much differencial in outside and inside pressure. Like Kiss said it could be from an open window or a door oppening up and the wind blowing in as the door is opened up . Good Luck And GOD BLESS ::: F.B.E. HELLO KISS F>B>E>

Well, there is probably different versions of caps. Think chimney caps, not plumbing caps.
Talked to a guy in the hardware store once who was making screens (caps) for his vents to keep the critters out.

Hey Gelsus:

Kiss is heading you in right direction.

Here is a pic. Of a few different roof vent caps that may help.. there are many other versions.

Check out www.plumbing supply for the dome cap.

Check out Septic Solutions Inc. - Serving Your Wastewater Needs for the dome shaped filter vent (click on online store at left.. then scroll down to find this)

Couple of them are filter caps, primarily for septics, but may work well here, too.

Let us know what you think... Mark

I agree with Mark. You can add caps to deflect the wind and keep critters out but I'm still thinking this isn't your problem. When wind blows across your vent pipe it does not blow downward, if anything it oulls air/gas up the pipe due to the Bernoulli principle you learned about in science class. YouTube - Bernoulli Principle If your traps are all working then I'd suspect the sewer gas is rolling off your roof and getting pulled inside the house. Do you know if any of your fixtures have AAVs instead of a P trap?