Common Sewer Issues

Sewer Odor

Sewer odor coming inside your home is a common issue.  This can be caused by dry traps.  This can be from a sink that is rarely used or a floor drain that is always dry.  The video below explains how pipes work and what other issues can cause sewer gas.

Blowback During Sewer Maintenance Cleaning

Blowback is an eruption of air and water discharging incorrectly from a plumbing fixture drain.  Blowback can be caused by a plugged vent stack, or inadequately designed plumbing.

Blowback most often happens during the sewer maintenance cleaning process.  During the process a jet nozzle and hose are inserted into a manhole, water pressure is then used to propel the nozzle and hose up the main to the next manhole.  Then the jet nozzle is slowly pulled back to clean the inside of the main and collect the debris at the downstream manhole for removal.  This process is used to remove accumulation of roots, grease, sludge, and grit that have built up over time.  Through this maintenance effort, the chance of sewer back ups is decreased and capacity of flow is restored to the main.

During this cleaning process, while the nozzle is propelling itself up the line, a negative pressure is created ahead of the nozzle while a positive pressure is created on the back side of the nozzle.  The amount of positive or negative pressure created by the nozzle varies with the pump pressure and water volume used to propel the hose up the line.  As the nozzle moves through the line, it passes house laterals in a fraction of a second, causing rapid change from negative to positive pressure.  This positive pressure pushes back into the service lateral line.  If there is nowhere for the positive pressure to go (through a properly vented stack) then it will force its way out through the plumbing fixtures or floor drain, thereby creating blowback.