informed
WATER DEPARTMENT
Sewer Cleaning Program
Sewer pipes in the North and South areas of Rockwood are cleaned every two years. It takes a few
hours on each street. The Township does not use chemicals; clean water is used to loosen debris and
flush pipes. A high-powered vacuum then removes debris from the pipe, and the debris is then taken
to a wastewater treatment plant for processing and disposal.
WHAT IS A SANITARY SEWER SYSTEM?
Rockwood has a sanitary sewer collection system
which transports wastewater from homes and
business to the centralized location for treatment,
which is provided by the City of Guelph’s
Wastewater Treatment Plant. The Rockwood
system has over 20 kilometers of gravity sanitary
sewers, five sewage pumping stations, and
one pretreatment plant which sends sewage to
Guelph. The sewers within Rockwood rely on
gravity to function and provide minimum flow
velocity to keep the sewers clear
and flowing. Over time materials
such as grit, sand, gravel and
greases settle out and remain
in the sewers with the potential
to cause backups and sewer
surcharging, which can result in
damage to property. Preventative
maintenance in the form of
sewer flushing ensures that the
gravity sewers continue to flow
freely, which prevents blockages,
odour generation, and
premature wear on mechanical
components within the
pumping stations.
WHAT IS SEWER FLUSHING?
Sewer flushing is a preventative
maintenance process necessary
to remove settled and accumulated material
within the gravity sanitary sewers to eliminate the
potential for sanitary sewer main surcharging.
DURING SEWER CLEANING
During this process a flushing contractor sets
up equipment at manholes in the roadway to
release pressurized water through the sanitary
sewer main, removing any buildup. As a result, a
bubbling and/or vacuum effect may be noticed
in your drains or toilets. If a resident notices this
occurring, it is recommended that you close all
toilet seats and cover any floor drains during
the flushing period. In addition, to eliminate the
potential of sewer gas migrating into the home, it
is important to refill all plumbing traps by running
water in your sinks and floor drains after work
is completed.
During the cleaning process, air
pressure is created inside the
sewer pipe. Most of the time,
the pressurized air escapes with
no impact. In some instances,
the air can only escape through
the service connection between
your house and the sewer system
and will expel through internal
plumbing vents without incident.
In some cases, a blocked sewer
pipe or vent within a home may
result in a more significant air
pressure release or blowback
through a toilet or floor drain.
The liquid which blows back is
either the flushing water used
in the process, or the liquid
contained within the toilet.
Unpleasant odours may also occur. Should
you experience a significant blowback, it is
recommended you have your plumbing checked
by a certified plumber to ensure that the service
connection and vent pipes are clear of debris and
functioning properly.
2022/2023 Edition
11
