In 1999, the City of Thunder Bay initiated a Downspout Disconnection Program (DDP), targeting areas that experienced sewage-flooded basements during heavy rainfall events, particularly in older residential/commercial neighbourhoods where downspout connections to the sanitary sewer (instead of storm sewers) were most common. The program has successfully reduced inflow and infiltration (I&I) into sanitary sewers, thereby reducing basement flooding during extreme rainfall events. Prior to the program, 70-100 basements would flood several times per year.

The City contracted with a private not-for-profit organization, EcoSuperior Environmental Programs, to aid property owners in disconnecting their downspouts. EcoSuperior delivered information to property owners in the target areas, raising awareness about “inflow and infiltration” and its impact on the sanitary sewer system, and explaining how disconnecting downspouts from the sanitary sewer could reduce basement flooding. At the same time, the city’s Rain Barrel Program was introduced as one alternative to redirect downspouts. The city offered 45-gallon rain barrels at a discount price of $40, available only to city residents with a water account. Rain barrels also played an important role in educating people about water conservation and reducing demand on treated drinking water, in that rain water needn’t be treated for uses such as grass/garden watering etc.

In total, 786 properties were identified by EcoSuperior staff, 64% of which complied and disconnected their downspouts from the sanitary sewer. Those properties not able to disconnect (for various reasons), are being dealt with as road/infrastructure upgrades occur.

Since 2000, the City has had no reports of basement flooding events due to sewer overflow. The requirement and expense of unnecessarily treating storm water at the City’s wastewater treatment facility has also been eliminated.

The Benefits of an Integrated Approach

As reported by the Ontario Centre for Municipal Best Practices (OCMBP), "the City of Thunder Bay has found efficiencies within their system by having both sanitary sewers and storm sewers being looked after by the same personnel in the Environment Division."

"The Environment Division’s structure of having both sanitary and storm water systems overseen by the same people increases the effectiveness of operations and maintenance related activities, along with project planning and customer satisfaction. "

"From a water conservation standpoint, the disconnection program gives property owners the opportunity to take advantage of the subsidized Rain Barrel Purchase Program to reduce their own treated water consumption, which in turn reduces municipal water and wastewater system operational costs. Along with the economic benefit, utilizing rain water helps conserve our natural resources as less fresh water requires treatment keeping water conservation issues and source protection at the forefront. "

The city is also saving money. As reported by the OCMBP:
"- Estimated savings of $17,000/year which would have historically been paid out in overtime to deal with rainstorm events (based on 2 events per year)
- Estimated cost savings from reduced insurance claims is approximately $60,000/yr
- Estimated savings of $980,000 from reduction of inflow and infiltration from 2000 to 2006."

In 2008, the City of Thunder Bay was recognized by the Ontario Municipal Benchmarking Initiative for a
Best Practice in Water and Wastewater for the City's Downspout Disconnection Program, which has been successful with reducing inflow and infiltration and alleviating basement flooding.

For details about Thunder Bay's award-winning Program, see the
Ontario Centre for Municipal Best Practices' Summary Report,
dated February 2008 (external link)

Through EcoSuperior, the city still offers subsidized rain barrels to promote water conservation. For more information on this program, go to the EcoSuperior website now.