Sanitary Sewer Inflow & Infiltration
CRD Inflow & Infiltration Program
The CRD’s Inflow and Infiltration (I&I) Program was created in the early 1990’s as part of the CRD’s Core Area Liquid Waste Management Plan (LWMP).
The purpose of the program is to reduce the amount of rainwater and groundwater entering the sanitary sewer system when it is cost-effective to do so. Reduction of I&I in the system lowers the risk of sanitary sewer overflows and can decrease the costs of conveying and treating wastewater.
The LWMP mandates a joint responsibility between the municipalities and the CRD in reducing sanitary sewer I&I.
- 2009 Inflow and Infiltration Biennial Report (30MB PDF
) - I&I Analyses Results 2006 to 2008 (50MB PDF )
Sanitary Sewer I & I Overview
Inflow and infiltration refers to rainwater and groundwater that enters the sanitary sewer. A certain amount of I&I is unavoidable and is accounted for in routine sewer design. However, when I&I exceeds design allowances, sewer capacity is consumed and may result in overflows, risks to health, damage to the environment and increased conveyance costs.
The following links are helpful for further understanding I&I:
- Sanitary Sewer Overflow Management Plan (16MB PDF )
- Overview of Sanitary Sewers & Storm Sewers
- Common Sources of I&I (PDF )
- Reasons for Reducing I&I
- Methods of Detecting Sources of I &I
Sanitary Sewer Maintenance Responsibilities
Homeowners are responsible for maintaining the sewer service laterals on their private property. Municipalities are responsible for maintaining sewers and sewer laterals on public right of ways. Read more 