Peterborough’s Rain Gardens for Private Property

Prepared by Kim Perrotta, June 2026

Background

In July 2004, the City of Peterborough was flooded when 9.5 inches of rain fell in a single day and overwhelmed the city’s storm water and sewer systems.  The fire department, utility and social services were inundated with calls.  One hundred and seventy-one people had to be evacuated from a long-term care facility.  Flooding resulted in 28 vehicle collisions and trapped 25 people in or on their cars.   Basements were flooding.  Electric meters and gas lines had to be disconnected.  And water heaters were damaged. Over a thousand residents needed emergency food and clothing.

“The 2004 flood made it clear that we needed a more robust stormwater management system in the city,” explained Curtis Mei, Acting Manager, Water Resources, Asset Management and Capital Planning with the City of  Peterborough. “It was the motivation behind the development of the 2005 City of Peterborough Flood Reduction Master Plan which laid the groundwork for the city’s work in this area.”  

Evolution of Stormwater Management

“There has been a learning process in the stormwater management field,” offered Mei.  “At first, cities worked to capture stormwater in grey infrastructure that delivered the water to a nearby body of water.  But that system delivered a lot of pollution picked up from roads and pavement such as dog waste, fertilizer, and vehicle leaks and emissions, directly into our watercourses.”

“Then it was thought that we should direct storm water to man-made settling ponds where the pollutants were captured, but those settling ponds have to be dredged which is a costly undertaking” Mei continued. “So now, cities work to control run-off at the source so that water can be filtered through the soil on the site where it falls.” 

“Recognizing that we need to manage the water that falls on private property as well as public property, the City’s Stormwater Quality Master Plan that was completed in 2011 recommended the establishment of a program for rain gardens on private property,” said Mei.

What is a  Rain Garden?

“A rain garden is a bowl-shaped garden that collects and absorbs the rain and melted snow that runs off impervious surfaces such as rooftops on a property,” offered Laura Keresztesi, the Coordinator, Neighbourhood & Residential Programs with GreenUP, a local environmental non-governmental organization.  “It is designed to have a shallow depression that is 20 to 30 centimeters deep.  It is planted with native species that have deep root systems that help absorb and naturally filter stormwater on site.  The bowl should hold water for up to 24 hours; it is not a water garden. The bowl of the garden should be planted with species that can tolerate ‘wet feet’. The top of the berms can be planted with drought tolerant species.  Choosing the right plants for each zone of the rain garden can help reduce maintenance as the garden matures.”

Rain gardens can remove 90% of the chemical pollutants and 80% of the sediment from stormwater runoff.  They also allow 30% more of the water that falls on a property to soak into the ground than regular grass lawns.

How does the Rain Garden Program Work?

The rain garden program began in 2020 with a collaboration between the City’s Water Resources team and GreenUP.

“Our goal is to encourage residents to incorporate rain gardens into their properties while promoting greater awareness of stormwater management and community involvement,” said Mei. “Rain gardens play an important role in reducing urban runoff from private lands, filtering pollutants from surface water, and replenishing groundwater supplies. They also enhance local biodiversity by attracting butterflies, dragonflies, and other beneficial insects, as well as native bird species.”

“The first few years of the program, we ran a number of workshops to educate people about how to design, install and maintain a rain garden,” said Keresztesi. “We found it was difficult for people to arrange their schedules around workshops so we developed instructional videos that are now available 24-7 on our website so people can access them at their convenience. Through our partnership with the City, we also offer onsite consultations and support people with their applications and installations”.

Each year, both organizations advertise the program with ads and social media.  GreenUP will also leaflet neighbourhoods.  Residents can get a one-time subsidy up to $1000 to help them establish their rain gardens.  The funds, which can be used to cover the cost of plants or to help prepare the garden, can be claimed with receipts once the project is completed.  

The City has hired GreenUP to make the program as friction-free and accessible as possible.  GreenUP answers calls from residents, distributes intake forms, conducts on-site consultations, and provides technical advice about the design of the garden and the plants that can be used.

Over the 5 years that the program has been in place, GreenUP has had direct communication with over 1500 people and assisted with the establishment of about 24 rain gardens on private properties.

Challenges and Lessons Learned

“There has been a lot of interest in the rain garden program from residents but only a handful move forward with one each year,” noted Keresztesi.  “Those who do move forward are quite committed to the idea of having a naturalized yard that supports biodiversity.” 

“Funding does not seem to be the barrier for residents,” offered Keresztesi. “Some residents cannot install a rain garden on their property because they do not have enough space.  For others, the rain garden is part of a larger landscaping vision and other things need to happen first before the rain garden can be installed.  For many, the barrier may simply be having the time and energy to dig, shape and plant.”

“We do allow residents to use the program funding for landscaper related costs to conduct the work,” offered Mei.  “We try to make it easy for people to claim the funds from the program.” 

“We have made the subsidy program available to community centres and schools.  While we have received inquiries from these organizations, there have not yet been any rain gardens installed on these properties.” said Keresztesi. “In some cases, the property was not eligible for the program, and in other cases, I think the teachers simply did not have the capacity to lead the project on top of everything else they are responsible for.”

“Currently the reduction of water volume to the storm water system has not been significant; that would require widespread implementation,” noted Mei.  “But the program has been very effective at educating the public about  stormwater management and the benefits of capturing water on site.  It helps them to understand the work the City is doing to prevent future floods, improve water quality in local rivers, and replenish ground water.”