Cracks in Pipes
If the rotten egg smell of gas seeping from the sewer or septic system is infiltrating your home regularly and does not seem to go away, then there may be cracked drainpipes in or near your house. This would be the most serious type of problem that could cause plumbing smells. In the event that a drainpipe has ruptured or cracked, the smell from the gasses below that are generated by the waste will likely be present most of the time in your home. The smell may come and go if the damaged line is buried in the yard, but if the broken line is located inside your home, you will likely notice it all the time.
This type of repair will require pipe replacement done by a professional. It could require some demolition, depending on where the cracked or ruptured pipe is located.
Clogged Vent Pipes
The culprit of smelly plumbing in your home may be something quite simple, yet very hard to detect. The pipes that stick up through the roof of your house are intake vents for the plumbing system. When water is sent down the pipes in the house, the gasses and air from the sewage are pushed ahead of it. The air in the pipes needs to be replaced, and it is sucked from the rooftop air through the vent pipes. However, when these vent pipes become clogged with leaves, a bird's nest, a ball or anything else, the blockage can force air to be sucked in from elsewhere. The air will be forced in through various fixtures such as sinks, toilets or other areas.
This, in itself, doesn’t cause the odor, but the traps at the fixtures can. P-traps are P-shaped bends in plumbing that are found beneath sinks, in toilet plumbing and anywhere else you run water down a drain. The shape of the pipe is meant to hold a bit of water to seal off the pipe so the gasses from the sewer system do not come back through the pipes and into the home. If the force of water going down the drain is significant, it can suck the trap dry when the vent pipes are clogged, which immediately allows the gas to escape into the home, according to the National Environmental Service Center website. Running more water into the trap should fix the problem.
Backdrafting is the act of drawing air up from another area using the energy of another source. For plumbing odor purposes, backdrafting refers to the use of an exhaust fan such as the ones found in many bathrooms. While the exhaust fan is supposed to remove odors from a bathroom, it can actually be the cause of more odors. The pressure caused by the turning fan can draw gasses up from the sewage through pipes in the room. This is generally not a problem unless there are dry traps that allow the free flow of gas to enter the room. Making sure the room has adequate fresh air intake is the key to preventing this problem.