Understanding Lot Drainage
These pages provide an overview of residential lot drainage and what you can do to lessen the impact of surface flooding caused by heavy rainfall.
In recent years, the frequency of basement and backyard flooding caused by heavy rainfall and changes to neighbourhood drainage patterns has increased. The City of Burlington and Halton Region have developed a number of programs and information materials to assist homeowners in understanding residential drainage issues.
Information from the City of Burlington is focused on how stormwater flows away from your home and how to improve lot drainage.
Information from Halton Region is focused on how wastewater from toilets, tubs, sinks and drains flows through the sanitary sewer pipes away from your home and steps you can take to minimize basement flooding due to sanitary sewer backups.
How rainwater flows away from your home
One-way or two-way drainage
The first step in ensuring proper drainage is to determine how stormwater is intended to flow from your property to the storm drainage system. Getting a clear understanding of how water drains from your property can go a long way in improving lot drainage and preventing future issues caused by flooding.
If your home was built after approximately 1960, grading plans were prepared at the time to indicate how water should be directed away from your home. Homes will have either two-way drainage meaning that stormwater would flow out over both the front and rear of your property (Fig. 1); or your home will have one-way drainage with water flowing in only one direction away from the property (Fig. 2). The City of Burlington has drainage plans for many properties in Burlington. Homeowners can view these plans by visiting the Engineering Department at City Hall.
The first step in investigating your property’s drainage is simple: Start by examining how stormwater drains away from your property. Look for swales and ditches and identify catch basins and creeks in your area. Consider how stormwater flows toward them. .
Does the water have a clear path to flow?
The most important step of all when considering your property’s drainage is to make sure that the water has somewhere to go. Often, changes made to the grade of the land due to landscaping, or the construction of sheds, decks, pools, or retaining walls can interfere with the path of rainwater as it moves toward the storm drainage system.
These changes can cause water to collect in yards or result in stormwater runoff being directed toward your house, making the building susceptible to flooding through door openings, window wells or foundation walls. Stormwater runoff directed toward your house can also overwhelm your foundation drain or sump pump system.
Much of the rain that falls is absorbed into the ground. By covering the ground with hard surfaces less water can be absorbed, increasing the amount of stormwater runoff and making the drainage routes away from your home more critical.