Global climate change poses one of the most challenging threats to the protection and longevity of critical infrastructure within our communities. One type of infrastructure that is affected by the increase in extreme rainfall events is our urban water systems, which are not currently designed to accommodate heavy, infrequent flows. Backwater valves were developed as a lot-level strategy to protect homes against water damage when sewers are running over capacity during storms. Although these devices were designed to reduce basement flooding, many individuals from the plumbing industry have reported that these valves have surcharged during heavy events. This thesis examines the performance of backwater valves under different operating conditions through extensive laboratory experiments. The results can be used to improve installation and maintenance procedures for these devices, increase reliability, and ultimately, reduce property damage and insured losses associated with basement flooding in Canada.