Metro Vancouver Reference Panel recommends action in managing flow from private sewer laterals
Metro Vancouver’s Liquid Resource Management Plan
Appointed by the Metro Vancouver Regional Board in April 2008 to provide independent advice and recommendations regarding the management of liquid discharges and rainwater, the Liquid Waste Management Reference Panel presented their Final Report on A Liquid Resource Management Plan for Metro Vancouver to the Waste Management Committee on July 15, 2009.
“Decisions we make on the built environment have a direct impact on the health of the natural environment. Our recommendations speak to the need to become more consciously aware of this interconnection in our planning, regulation and decision-making.”
The Inflow – Infiltration Issue
“In particular, the Reference Panel recommends that Metro Vancouver and its members resolve the persistent and costly sanitary Inflow & Infiltration Issue by acting on policy and legal tools that enable municipalities to implement timely and appropriate measures on private property,” states Shaun Carroll, an inflow-iinfiltration specialist and member of the Reference Panel.
“Not only is I&I a significant source of regional system overflows, it means we are repairing/replacing our pipes and pumps sooner, building treatment plants and pipe systems larger than necessary, using more treatment chemicals than necessary, and leaking raw sewage into the ground.”
Managing Private Sewer Laterals
A private sewer lateral refers to the pipe that conveys sanitary sewage from a private building to the public sewer system. Each municipality defines where the private lateral extends to in its bylaws; though typically in Metro Vancouver the private lateral ends at the property line.
The property owner is responsible for maintaining the private lateral; however, most private laterals tend to be neglected because they are not visible to the homeowner.
Overflows in the Regional System
“Private laterals are the last unmanaged part of the sewer collection system, and groundwater and rainwater entering from private property account for an estimated 40% of all wastewater collected, transported and treated by the Metro Vancouver regional system,” states Shaun Carroll.
“Because this is an issue throughout Canada and the United States, many jurisdictions are investigating and/or implementing programs to reduce the flow entering from private sewer laterals. These programs range greatly in their design, from voluntary incentive-based measures, to agency-led and funded programs, to mandatory compliance measures.”
Consequences of ‘Extra’ Sewage
“Before we had sewage treatment plants, leaks such as these into our sewer system were viewed as a ‘good thing’ – we valued the effect of dilution on our pollution. Not so today.” According to Shaun Carroll, some of the consequences of this “extra” sewage are:
Treatment plants must be built larger to handle the extra capacity.
The collection pipes must be built larger to handle the extra capacity.
Sewage overflows from the system when the pipes cannot contain the extra volume
Sewerage backs up into homes when the pipes cannot move the extra volume.
Raw sewerage leaks out of holes and directly into our grounds.
“All pipes and equipment that help to move, measure or treat the liquid discharges (i.e. pumps, meters, tanks, etc.) must handle more volume; therefore, they wear out sooner and must then be repaired or replaced,” she concludes.
A Path Forward for Metro Vancouver
The December 2008 report titled Private Sewer Lateral Programs: A Study of Approaches and Legal Authority for Metro Vancouver Municipalities provides a synopsis of the range of programs that have been implemented in other jurisdictions, analyzes these options within the context of the Metro Vancouver regulatory environment, and provides recommendations /pathways for moving forward.
According to Susan Rutherford (West Coast Environmental Law), report co-author and a member of the Reference Panel: “The research led to development of a sample bylaw ‘for the maintenance and repair of private sewer laterals’ for Metro Vancouver municipalities. The sample bylaw includes both an enforcement approach over the longer-term, and an incentive approach over the shorter-term.”
“A key feature of the sample bylaw is a Sewer Lateral Certificate. These would be given to property owners for compliance with the standards set forth in the bylaw.”