Basement Flooding Information

Stormwater infrastructure is managed through a combination of systems. The Ontario Drainage Act provides a framework for drainage in rural areas, where shared systems are designed, constructed, and maintained with costs distributed among benefiting landowners. These systems are designed based on typical storm parameters and in accordance with provincial regulations and best practices, and they cannot be designed to prevent flooding in every condition. Additionally, not all ditches and storm sewers fall under this Act. In urban areas, infrastructure may include municipal systems and Drainage Act systems. In addition, some private drainage systems may be privately owned and maintained between properties, and do not fall under either framework. 

Most homes have two (2) types of private drain connections (or PDC): 

• Storm or groundwater (examples include sump pump connections, downspouts, weeping tiles, rear yard catch basins) 
  
• Sanitary connections (examples include toilets, sinks, floor drains, showers) 

 The PDC's direct the storm or sanitary water from your property to the municipal sewers (typically located within the road allowance). Sometimes items that should be connected to your storm PDC are actually connected to the sanitary PDC, which is not recommended or acceptable. If you are unsure of your existing connections, it is best to hire a licensed plumber to flush and inspect them via camera. 

Common causes of basement flooding 

Basement flooding can result from one or more of the following conditions: 

• Private drain connection (PDC) issues: Most homes have storm or groundwater connections (such as sump pumps, downspouts, weeping tiles, and rear yard catch basins) and sanitary connections (such as toilets, sinks, floor drains, and showers) that direct water from the property to municipal sewers; if storm-related services are connected to the sanitary side, or if these connections are blocked, damaged, or improperly configured, the risk of basement flooding increases. 
  
• Sewer backup: During large rain events, storm sewers and ditches can become full, and pump stations may reach their maximum operating capacity to move water downstream. When this occurs, sump pumps and private stormwater systems may not be able to discharge properly into municipal storm sewers, increasing the risk of basement flooding. 
  
• Foundation leakage: Water can enter through cracks or other openings in foundation walls or basement floors, especially when the ground around the home is saturated or groundwater levels are high. 
  
• Overland flooding: Heavy rain may collect on the ground surface and flow toward the home. Water can enter through low openings such as window wells, stairwells, garage areas, doors, or cracks near the foundation if the lot does not drain away from the building. 

Overland flooding and lot grading 

Overland flooding happens when rainfall cannot soak into the ground or enter drainage systems quickly enough, causing water to pond or flow across the surface of yards, driveways, and streets. If the ground around a home slopes toward the foundation, that water may collect against the house and enter the basement. 

• Ensure the ground slopes away from the foundation so rainwater drains away from the home. 
  
• Keep swales, ditches, rear yard catch basins, and other drainage routes free of debris. 
  
• Extend downspouts to discharge onto an absorbent surface, such as a lawn or garden, and away from the foundation. 
  
• Do not direct runoff toward neighbouring properties, sidewalks, or areas where water may flow back toward the building. 
  
• Check window wells and exterior stairwells to make sure they drain properly and are clear of leaves, soil, and debris. 

How residents can help reduce the risk of basement flooding 

• Disconnect downspouts from private storm drains where appropriate and direct water to an absorbent surface away from the home. 
  
• Ensure sump pump discharge is directed to a suitable location away from the foundation. Consider a check valve and a battery or water-powered backup system in case of power failure. 
  
• Maintain eavestroughs and downspouts so they are free of leaves and debris. 
  
• Keep yard catch basins, swales, and drainage routes clear so surface water can drain properly. 
  
• Seal cracks in foundation walls and basement floors where water may enter. 
  
• Avoid pouring fats, oils, and grease down household drains, which can contribute to blockages in sanitary plumbing. 
  
• Reduce home water use during major rainfall events to lessen the load on sanitary systems. 
  
• Ensure storm services such as weeping tiles, downspouts, and sump pumps are not connected to the sanitary drain. 
  
• If no storm services are connected to the sanitary side, consider installing a backwater valve on the sanitary drain to reduce the risk of sewage backup. 
• Have both storm and sanitary private drain connections inspected if you are unsure how your home is connected or if you have experienced previous flooding.
  
• If you are near farmland, ensure there are no old field tiles close to your foundation. If found, they should be excavated and plugged as far away from your foundation as possible. 

Steps taken by the municipality to address basement flooding 

The Municipality has completed stormwater master plans for Tilbury, Ridgetown, and Shrewsbury and continues to implement their recommendations. Information on the status of these plans can be found here: https://www.chatham-kent.ca/services/stormwater/Pages/Stormwater-Projects.aspx. Stormwater master plans for Blenheim and Wheatley will be initiated in 2026 to identify upgrades and long-term strategies to improve stormwater performance and reduce flooding risk. More information will be made available to residents as these projects are initiated later this year, and this will include public consultation to identify concerns, receive input and help inform the study process. While these plans support long-term improvements, storm systems cannot be designed to prevent all flooding. Private property conditions also play an important role, 

When to seek help 

If you are unsure how your home's private drainage is connected, or if you have experienced water entry or sewer backup, consider hiring a licensed plumber to inspect the system using a camera. Residents with drainage concerns such as road or private property flooding can contact the Municipality through 3-1-1 or submit a service request online. During emergency situations, residents are encouraged to stay informed through municipal emergency communications.