A sewer smell in house can be very annoying and even exasperating for the typical homeowner. In some cases a sewer smell can even be found just outside one’s home. For a person unfamiliar with common plumbing problems, a sewer smell problem in a house can be difficult to solve. For a knowledgeable plumber a sewer smell problem is relatively easy to diagnose and easy to cure. There are three main causes of this annoying problem, and none of them requires major plumbing repairs.
An open sump or an improper drain creates many issues for concern. Not only can they produce foul sewer smells, but there can be health issues as well. Plumbing short cuts typically end up costing more in the end to correct. And they affect quality of life in the interim.
Sewer smell in house from loose or ill-fitted sewer trap plugs
The most common source of a sewer smell in house is from missing, ill-fitted, or loose sewer trap plugs. The sewer access pit is the first place to check, and maybe the last place most people look. In the bottom of most access pits in a basement is the house trap.
A house trap us U shaped so water sits in the bottom of the trap. This water serves as a barrier between sewer gases from the city sewer, and your home or business. If the sewer trap is not properly sealed with trap plugs, a sewer smell will be present from sewer gases escaping from the public sewer.
Most house traps are double vent – meaning they require two plugs or caps. There are two openings in order to allow for the drain system to be easily cleaned in each direction. Replacement plugs or caps are extremely inexpensive, costing around $10.00 or less each. In older house traps a fit-all plug can be used. Fit-all plugs are lead lined and can conform to the irregular or worn openings in older house traps.
Wing nut test plugs are a great option when replacing plugs on an old house trap. They are air and water tight. The are re-usable and require no tools to install. On the downside, they are usually a special order from a plumbing supply house, and you will have to supply the accurate size you require. To get an accurate size, simply measure the inside diameter of the opening in your sewer trap.
Sewer smell in house from a dried out house trap sump
The 2nd most common source of a sewer smell is from a trap whose water barrier has dried out. As mentioned previously, one of the main functions of a trap is to provide a water barrier to keep sewer gases out of your house.
All plumbing fixtures and house sewers are supposed to have a trap. Most plumbing fixtures have what is known as a P trap. An example of a P trap can be seen if you simply look under your kitchen sink.
If a fixture is little used, such as in a guest bathroom, or a seasonal residence, the water in the trap can evaporate. Simply running some water can resolve the issue. The same applies for either a little used fixture, a guest house, or a vacation home. Simply running some water will fill the trap belly back up with water, and re-create the water barrier.
Sometimes pouring some vinegar down a drain can help to get rid of a foul odor. But a sewer smell in house should not be taken lightly either. A sewer smell is indicative of methane gas and bacteria being present in the air. Headaches can result, but if left untreated there can also be health consequences as well. If you smell sewer gas act promptly.
Sewer smell outside house from leader line or area drains
A sewer smell outside your house can mean that the city sewer is backed up. But if the smell is constantly present it can have to do with your roof leader line outlets, or area drains.
Although storm sewer systems should not contain sewer gases, sanitary and combined sewer systems do. That means if your roof leader lines or area drains are connected to a combined, or sanitary sewer system, they can be the source of your sewer smell.
Just like all plumbing fixtures roof leader lines and area drains are supposed to have a trap to provide a water barrier. If outside roof leader lines connect to your combined house sewer outside your house (the combining point), each leader line drain must be trapped. Otherwise sewer gas will escape between the roof leader line and where it enters the underground drain. A trap for a leader line or area drain can be present either inside of outside the building. Either location is legal and meets code.
One can attempt to caulk up the gap between the roof leader and drain, but that is not the proper solution. The proper solution is to install a P trap underground for each roof leader outlet. It is also important that the trap be below the frost line so the water inside the trap does not freeze in the Winter time.
In most cases area drains and roof leader lines are run inside the building. They then have a separate trap for the storm water, alongside the sanitary water trap located near the front of the building. Most leader lines and area drains usually still have their own trap to catch debris and sediment.
Annoying and hard to diagnose plumbing problems
There is a common theme regarding many common plumbing issues, such as a sewer smell in house. The common theme is that a low cost fitting or part was not installed properly, or not installed at all. Whether intentionally or not, a missing $10.00 sewer cap or $100.00 trap can cause all kinds of inconvenience, and possibly health issues.
Professional grade plumbing work requires closely adhering to approved plans and to applicable local plumbing code. While it may be tempting to hire an unlicensed tradesman in an attempt to save money, the outcome may not be so positive. Correcting inferior plumbing work can be costly, and have health and quality of life consequences in the interim.