What is That Smell?

Every now and then you get a whiff. Sometimes its faint, other times it could just about knock you over. It may be in the front yard or on the back deck, in the bathroom or the kitchen. You know it has something to do with the septic or sewer system, you can tell by the smell, but you can't quite pinpoint the source or decipher the cause. And then it's gone until the next time.

Here are a few reasons you may experience septic and sewer odors in and around your home off and on.

1. A dry p-trap in an unused drain.

Each drain in your home has a p-trap. A p-trap is the U shaped section of the drain pipe under your kitchen and bathroom sinks. The function of the p-trap is two fold. It helps prevent solids from going down the drain while holding enough water to prevent sewer gas from coming up the drain and escaping into the house. When there is no water ran through a drain for a long period of time the water in the p-trap evaporates. With no water in the p-trap to stop it, sewer gasses can rise up and out of the drains and cause unflattering odors in your home. The solution is to periodically run water through all of your household drains including the floor drains or utility sink drains in the basement or garage that seldom get used.

2. An outside ventilation problem.

Some septic and sewer systems have roof vents, some have a vent that comes out of the ground between the house and septic tank or sewer main. Each toilet in your home should also vented. Most of the time as long as installed properly these vents will allow septic and sewer gasses to excape without notice. But there are times that this may not be the case.

a. Unusual down drafts can cause noticable odors from time to time from a roof vent.

b. There may be times in the winter that a vent becomes frozen or blocked by snow and may not vent properly causing gasses to escape elsewhere. If it is a vent in the ground the solution may be as simple as moving the snow away and pouring some warm water through it. As for roof vents that may be a little trickier and you may want to call a professional.

c. Roof vents may become clogged with leaves and debris or even bird nests, if you suspect this is the case you should have the vent cleaned of debris and have a proper vent cap installed to prevent birds and debris from getting in.

3. I have taken calls from time to time from customers who described "a rotten egg smell". In this case I always ask if they have natural gas. If the answer is yes, I first suggest is that they call their natural gas company to make sure it is not a gas leak. It is my understanding that because natural gas has no odor, gas companies add a chemical that has a rotten egg smell so that a leak can be detected.

There are times when even a professional will have trouble pinpointing a sewer gas problem and may need to return multiple times to even detect the odor. Therefore, it is a good idea to keep note of when and where you notice the issue, what drains were in use at the time, and what the weather conditions were.

In any case, we are here to help locate and correct any septic or sewer odor problem you may experience.