Why is there a sewer smell in my house?

Sewer odors in a house are caused by a problem in the plumbing system. Here are the most common causes:

Causes and solutions:

• Dried-out trap: The trap of a floor drain, sink, or shower that hasn't been used for a while has emptied. Solution: refill the trap of each unused drain with water — the trap seal is what blocks sewer gases
• Blocked vent: Leaves, bird nests, or ice are blocking the roof vent. Solution: inspect the roof, clear the vent. Plumber cost: $100 to $250
• Broken toilet seal: The wax ring under the toilet is leaking. Solution: replace the wax ring ($5 to $15). If the odor persists, the toilet may be cracked
• Broken or clogged sewer pipe: A partial clog creates pressure that forces gases through traps. Solution: drain cleaning and camera inspection ($200 to $400)

Warning: Persistent sewer odors may indicate a sewer gas (methane) problem. Open windows and contact an RBQ-licensed plumbing contractor (subclass 15.5) promptly for diagnosis.