Background
Lethbridge receives approximately 275 millimetres of rain each year, most of which falls from May to October. Our spring and summer storms tend to drop large amounts of rain over short periods of time. During major rainstorms the sheer volume of water can back up drainage systems and flood basements.
Goal
The City of Lethbridge wants to be proactive in communicating with residents about how to protect their homes from flooding. We want to share with you the common reasons for basement flooding and the many things you can do to prevent basement flooding.
Common reasons for basement flooding
- Overloading of the wastewater and stormwater collection systems.
For more detailed description click here.
- Poor lot grading may contribute to basement flooding.
- Plugged or damaged eavestroughs and downspouts
- Downspouts not being extended
- Water from window wells
- Cracks in basement floor and foundation wall
- Leaking weeping tile
- Sump pump and backwater valve not working
- Gutters and stormdrains plugged with debris.
Sump Pump Design - Criteria for design
(click on the diagram below to bring up a larger pdf version)

What can you do to help prevent basement flooding?
What do I do if my basement is flooded?
Basement flooding-Next steps
Subsidy Program
Protective Plumbing Incentive Program - The purpose of the program is to offer owners of older homes an incentive to reduce their risk of sewer backup. The program is currently limited to homes built before 2000 and that have
experienced sewer backup.
Resources
Protect Your Home From Flooding-A guide for Lethbridge residents
Handbook for reducing basement flooding - Designed for Safer Living
R is a program endorsed by Canada's insurers to promote disaster-resilient homes. Find out more about how you can reduce your chances and your neighbours' chances of having basement flooding.