Roaring Noise in a House Sewer Pipe

High Pressure

• Very high water pressure may cause pipes to roar or knock. This problem is called “water hammer” and can eventually crack your pipes or cause leaks. This problem happens most often in older homes, where smaller pipes restrict the flow of water. Newer houses usually contain a pressure regulator that keeps water hammer from occurring. If you have hammering problems, install pipe risers or water hammer arresters at each valve junction or faucet.

Transmitted Sound

• A flushing toilet or draining shower may cause your drain pipes to gurgle, make trickling sounds or roar. This happens when poly vinyl chloride, or PVC, drain pipes are used in the wall. Since PVC transmits sound more effectively than old-fashioned cast iron, drain noises come through the pipe and into the living space. The roar of a flushing toilet or the trickle of a draining washing machine sounds loud and intrusive. Building expert Tim Carter recommends replacing the PVC pipes with cast iron or wrapping the whole pipe with fiberglass sound batts to reduce noise transmission.

Poor Venting

• Especially in older homes, poor plumbing design can lead to unpleasant noises, smells and bad performance. Double S-traps on sinks, unvented fixtures and vacuum breaker drains often allow air into the pipes, creating loud sounds and slow draining. This also happens in fixtures where the vent is too small or doesn't extend outside the building. Even well-vented fixtures can develop noise and draining problems when small animals or insects nest inside them, partially blocking the airway. Check the vent; install new vents and traps if necessary.

Blocked Drain

• Partial drain blockages can make your sewer line gurgle or produce other unpleasant sounds. When all the fixtures attached to a particular line drain slowly, a blockage is often the problem. Blocked septic systems or sewer piping produce similar results, but usually appear normal until you use several draining fixtures at once. Doing large loads of laundry or flushing the toilet while running water elsewhere may produce a slow, backed up or noisy drain. Most sewer pipes and septic lines must be cleaned by professionals.