Put your house up for sale this summer and only show it on days you're upwind from the smell...?
Yes, I thought the same thing, but the blower/smoke test did not indicate any leaks, in any of the houses in question. They all, however, simultaneously exhibit the very strong smell of sewer gases (4 houses total). Previously, when the man-hole cover in question was the vented variety, the smell inside would always coincide with the smell outside. One didn't happen without the other. Now that the man-hole cover is solid, things are different as there is more of the smell inside the homes than previous.If the sewer gas is entering directly into your home (not just ambient gas outside entering through windows, doors, or house leaks, you have a vent/seal problem.
Maybe you have a dry trap, maybe a leaking vent. If your house is reasonably tight and you run an exhaust fan you could be drawing in sewer gas to make up for the air exhausted out.
Try doing the opposite, pressurize your house. See if that changes things. If the smell is in the ambient air outside, you cannot fix the problem without fixing the sewer system.
I asked the same question to the city workers, including the public works director, all to no avail. No one had an answer, at all.A couple of questions come to mind.
1. Why did the manholes have vented lids in the beginning?
I am assuming the one in my front yard was changed due to someone complaining about the smell. Of course, this was prior to my arrival here in 2006. The lid down the street (at the beginning of the gravity fed system) was change about a month ago to alleviate the complaint regarding the over-powering sewage smell coming from that location.2. Why were the vented lids changed to unvented lids?
I would guess out the roof vents of the houses in close enough proximity?3. When a presssurized line is pumping, where is the displaced gas supposed to go?
The first was done about 3 weeks ago, and the last one was about 2 weeks ago.4. What time of year was the smoke test done?
Central North Carolina, about 30 miles south of Greensboro and 45 miles west of Raleigh.5. What is your location?
Yes, this is an interesting phenomena, but I don't believe it has anything to do with the problem my neighbor and I are experiencing. This is merely my opinion based upon the smoke pouring out all the vents penetrated the rooftops on each house during the smoke test, as well as this intermittent problem also occurs at any point during the year. It is, however, more prevalent during the winter months.I'm in central Iowa and we have had some below zero weather for the last few weeks, along with some snow. I got an email from a lady this morning asking about some new gurgling sound in her shower when a toilet is flushed. I responded by asking her if she had noticed anything outdoors which could have contributed to the problem. She couldn't figure it out, so I told her that her vent line was probably plugged and it wasn't anything to worry about and would probably be fine as soon as we get above freezing again (thursday). I have noticed a few vents just from the street with caps of snow on top of them.
Yes indeed, but I have no Studor vents in the house, and I have ran a 1-inch clean-out snake down the vent on the roof, as well as ran the water hose up on the roof and let the water run in the pipe for about an hour. I never saw any issues.Jeff, you said you noticed bubbles coming through the water in the trap. That shouldn't happen though it could if a studor-vent was used or the roof vent is plugged or improperly installed.
Those bubbles are a likely candidate for the sewer gas and the smell.
What is odd to me is the fact that the city has never performed a smoke test prior to the recent ones. In fact, I never knew such a thing existed.I was thinking the smoke test was done when the weather was warm and the vents were open and they had maybe frozen shut since then.
I can't really attribute the occurrence to any specific thing. Sometimes it's sunny, sometimes not; the only thing I have noticed is it tends to happen more frequently during winter months, sometimes the temperature is really low, sometimes it is not.Could atmospheric pressure have something to do with this? Does it get smelly when it is overcast and no wind and maybe drizzly, or does it happen when it is sunny and windy and clear weather?
I have asked about 4 days ago, and have had no response as of yet. We have, however, had a lot of snow and ice recently and perhaps this has something to do with the lack of a response as of yet.Is the municipality willing to put the vented lids back on and do a sort of practical test?
True enough. My concern revolves around a remedy more so than a general understanding of the physics involved; but I have been hopeful of a better understanding of what's actually going on could help lead to me asking better questions that might lead to a solution, maybe. At this point, I am learning a few things about the issues going on, but I am still quite unfamiliar with much of the particulars.I guess we don't really have to understand what is happening if a solution can be found.
There are only the 2-two-inch lines (the pumped sewage lines) feeding into the man-hole, which is about 9 foot deep and 2 feet in diameter.I have installed quite a few septic systems in rural areas that are not on town sewers. Many use a pump chamber and pump to get the effluent to the septic bed. The pipe from the pump chamber goes to a distribution box which divides up the effluent and sends it down each line in the bed. The man hole you speak of is similar to our distribution boxes except it only sends the effluent out the 8 inch pipe. Is it possible that when the situation happens that several of the homes on pumps as well as the gravity ones are all sending effluent to the chamber at the same time.
Very interesting analysis. Thank you for pointing that out!Would this fill the man hole up to the point that it would be so full that it would have no choice but to pull air down the lines of the gravity feed homes. This wouldn't happen under normal circumstances as long as everyone wasn't using their system at the same time. This would explain why it would pass the smoke test, and why it wouldn't do it with the vented cover on the man hole. Maybe it is requiring more air than can be supplied by your main vent stack and is drawing the water out of your traps to get more air. If the smell is inside the house it must be sucking the traps dry.
I personally don't have an answer to some of the points you've brought up, like the inadequately sized man-hole. As noted above, it is, however, quite a large man-hole, but then again, I haven't a clue with how it compares to "proper size," or rather, what it should be.This might explain why it happens in the evening probably when everyone is doing laundry, having showers, dishes ect. Maybe the manhole is undersized for the effluent going into it.
No, I haven't been able to associate it with a specific fixture, or occurrence.Do you notice the smell from a certain fixture or perhaps a floor drain for a furnace or something.
I do pour water into the traps, but to no avail.If you pour water down all the traps does the smell stop temporarily.
Here's the rub, Thom (at least in my mind). The house was built in the mid-1950's, and I have no exhaust fans in the kitchen or bathroom, or a fireplace. The only thing I do have is a dryer, and I have not been able to associate the smell with the use of the dryer, as the problem occurs mostly when the dryer isn't running.Bubbles in a trap is a clue. That can only happen with pressure differential. The sewer is pressurized more than your house.
Maybe the sewer, maybe the house.
You can test the house with a manometer. It will measure the difference between indoor pressure and outdoor pressure. You could test the sewer the same way. That will at least tell you if the problem is the house or the sewer. Either the sewer is being pressurized above ambient (outdoor) or your house is pressurized below ambient.
If the house is pretty tight there is a chance it's the house. When anything is removing air from the house it must be replaced from somewhere if not through leaks, then through the sewer and traps.
Really, low indoor air pressure is not very unusual. Any vented gas appliance without supplied make-up air can cause it. Any exhaust fan, a fireplace, or a clothes dryer vent. If there is a decent breeze/wind an open window on the down-wind side of the house can be the culprit. If you have a mechanically vented crawl space (radon) and the crawl space vents are covered....
If the plumbing system in your home is properly vented it seems to me the more likely culprit is low indoor air pressure.
I have already replaced the wax ring, but I will try extending the vent pipe (I wouldn't think it can hurt anything), as it is now only about a foot above the roof surface.I was building a pair of townhomes next to another pair and it was in November. That is when I noticed a terrible smell around the townhome closest to the new construction. I had never smelled this before or had it reported to me. They were energy star and very tight.
The smell seemed to go right down into the hole for the basement next door, so I asked the guys forming up if one of them had shat his pants or forgot to brush his teeth or something.
It was horrendous.
I went into the townhome closest to the smell and pulled the toilet and replaced the wax ring.
I talked to a plumber friend and he recommended extending the vent pipe up, so I put a coupler on the 3" line and brought it up above the ridge by about 3'.
That seemed to take care of the problem.
I haven't had any reports of a nasty smell there since, but then again that forming crew hasn't been back either.
Sometimes someone will ask why the pipe on the one side of the building is higher than the other. I guess you could call it a conversation piece.