Smelly basement caused by drain vent?

[kepi13]

My basement smells. I have checked everything. None of the pipes are leaking and there is no standing water. I even taped a sheet of plastic to the floor and walls to see if there was any moisture seeping in and they are both dry.

We do have really poor plumbing in our laundry area that also feeds the kitchen. It was a really bad DIY job from years ago. Drain pipes sloping upwards, an old sock stuffed into a waste line connection, and, what I think is our smelly basement culprit, the vent stack vents directly into the basement. There is nothing from the toilets venting through this, just water from the kitchen sink and from the clothes washer.

Could this be the cause of my smelly basement?

[HayZee518]

Could very well be - but I would ask lazypup - the resident plumber of the home forum. do THOSE drains go into a septic system or the town waste lines? A stack vent is supposed to go from the sewer line all the way to above the roof line to vent off sewer gases either from a septic tank or the town sewer line. Waste arms from sinks and laundry are supposed to be pitched 1/4 inch per foot of their run. Each waste arm needs a trap to contain the gases.

[kepi13]

The drains go into the town waste line and there is only 1 trap that's on the tub sink in the basement. That is the drain that slopes upward. It leaks.

[HayZee518]

take THAT drain line apart and re-pipe it. use the 1/4" inch per foot DOWNWARD pitch towards the drain. There's no other traps on the other appliances in the house?

[LazyPup]

Allow me to begin by asking you a question.

What would be your immediate reaction if someone came and told you they just spilled a quart of gasoline on your basement floor or if they said there is a natural gas leak in your basement?

I don’t mean to unnecessarily alarm you, but if you have an open vent in your basement as you describe you need to immediately seal that pipe with the same level of haste as you would to clean up the gasoline or correct a natural gas leak.

While most people only think of Sewer gas as having a foul and offensive rotten egg odor, in fact sewer gas is a varying composition primarily of methane or Hydrogen sulfide but it may also contain a number of other potentially deadly gasses, which may not even have an odor, or to make matters even worse, gases that have the ability to mask their odor by turning your nose off.

Sewer gas is produced by the decomposition of organic matter such as fecal matter, vegetable matter, meats scraps, fats, cooking oils, toilet tissue and other forms of organic matter that is present in the sewer lines.

The decomposition process generates such gases as;

Hydrogen sulfide-
Rotten egg smell,
Asphyxiate. Flammable and potentially explosive
In low concentration Hydrogen sulfide has a rotten egg odor however in higher concentrations it has the ability to anesthetize the olfactory nerve so you may smell it at first but as the olfactory nerve is anesthetized you can no longer smell the gas and you are left with the illusion that the gas has dissipated.

Methane-
Odorless
Asphyxiate. Flammable and Potentially Explosive.
The natural gas that we use for fuel is comprised of approximately 90% methane. In its natural state Methane is odorless however when it is processed for use as “Natural Gas fuel” a stanching agent is added to produce the pungent smell that we all commonly associate with natural gas.

Asphyxiates;
Sulfur dioxide
Ammonia
Carbon Dioxide
Nitrous Oxide

In addition to smell, some of the other indicators of sewer gas are watery eyes, headaches or itchy skin.

Almost everyone who has worked on chrome plated brass P-traps and drain lines has encountered old brass pipe that has corroded through and is crumbly. Have you ever wondered what caused that pipe to corrode in such a manner? Given that there is no iron in a brass pipe we can rule out rust. The answer is the same thing that causes acid rain, hydrogen sulfide. When hydrogen sulfide combines with water vapor it produces Sulfuric Acid. If hydrogen sulfide happens to combine with the sweat on your skin it produces a mild form of the acid, which then causes your skin to itch.

It must also be noted that some of these gases are lighter than air, while others are heavier than air therefore the sewer gases may stratify in a layer near the floor or ceiling and go totally undetected. I recently read of a very tragic incident where a housewife had placed her infant son in a playpen while she was doing her laundry and cleaning the family room in their basement. She thought nothing of it as her child slept quietly in the playpen, but later, when she finished her task she picked up the child to find that the child was not just sleeping, but in fact nearly dead. An investigation concluded that the child had suffocated from sewer gas that came in through a floor drain from a dry trap nearby the playpen. The gas had stratified near the floor thus as she was on her feet doing her chores her nose was 4’ above the floor and she never had any indication that the gas was present. The investigation further concluded that the laundry dryer had contributed to the problem because as the dryer we running it was venting air out of the room, leaving a slight negative air pressure in the room which literally sucked the sewer gases in and across the playpen before being discharged out through the dryer.

So far I have discussed the gaseous hazards that are naturally present in sewer gas, but we must also consider the man made hazards as well. Every day we literally pour millions of gallons of household chemicals down the drain without giving it a thought. There is no of telling what chemical reactions that might be taking place or the types of gasses they may produce in the municipal sewer lines at any given moment, but here again, these are reactions of the normal lifestyle. Taking this to the next step, we have the hazards that are produced by gross stupidity.
Last fall in Columbiana County, Ohio a fairly new on-story house literally blew up without warning. Mind you, this was not a little explosion in a corner of the garage; the house was literally lifted off the foundation. At first it was thought to be the result of a natural gas leak, but it was later determined that the gas system was totally intact. The local sheriff and fire marshal then thought perhaps someone was attempting to manufacture met amphetamine or perhaps explosives so they called in the state arson investigator, who in turn called in the FBI crime lab. It was finally concluded that a neighbor had intentionally poured 20 gallons of old contaminated gasoline down the drain to dispose of it and the fumes from the gasoline being lighter than air had entered the house through a floor drain and had been ignited by the electronic igniter on the furnace.

As if sewer gas is not problematic enough, consider this. As liquid flows through a drain pipe it pushes the air and sewer gas in the pipe ahead of itself. This creates a positive pressure that is properly relieved by going up and out the roof vents, however if you happen to have open vent lines or dry traps the air and sewer gas is pushed out into your living space. In addition to aforementioned dangers of sewer gas keep in mind that there are any number of dangerous pathogens in the form of germs, spores and bacteria that can also be spewed out with that air and gas. This can be dangerous enough in the close proximity of the drain or vent opening but if that air should happen to be drawn into your HVAC system those pathogens are then distributed throughout your homes atmosphere.

From this I hope you can see that while most homeowners and DIY’ers simply think of DWV venting as a necessary evil to get through a plumbing inspection, you can rest assured trained plumbers and plumbing inspectors consider venting the most critical aspect of the whole system.

If you could post some pictures of the piping and layout in your laundry area I would be glad to work out a solution so that you could upgrade it to current code standards.






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[citydrains]

smelly basement

Sounds like you already know the source of the smell!
If there's no moisture collecting or water leaking, the smell must be coming from elsewhere - best would be to get a plumber in to have a look and advise.
Hopefully if you rectify the dodgy DIY section your problem should be solved.
Is it an old property?

[KFS]

Rotten Egg smell in basement

Old house
Septic
Kinetico Water System
No natural gas service
Uses outdoor woodburner that pushes water 200' across backyard into hot water radiators
Electric hot water tank

Starting about a month ago we get a random "rotten egg" odor. I am familiar with both the smell of septic/sewer AND the stench of a high sulfur well water (which we have - hence the Kinetico).

We notice it most after laundry and probably after the Kinetico system has reacharged (ie this morning after showers).

The laundry/softener drain does NOT drain into the septic but into a separate drain. We cleaned out that drain assuming snow/ice during the winter was the culprit. It seemed to help but today the stink is back and stronger than ever.

The basement is wet in one corner and has heavy drainage into that softener/floor drain today. However there is no leakage/seepage from septic/toilet lines.

On wet days drainage into the floor drain is slow but that's been for YEARS. The SMELL is new and has us confounded and is driving me nuts! Who wants the beautiful home that smells, forgive my language, like a giant fart?

We have lived here for fifteen years and only had this problem in the last month or so.

We are overdue for a septic pump and have that scheduled but since no other drains/flushing is an issue AND the laundry/softener don't drain into the septic, I'm at a loss as to how that could have an impact?