**Direct answer:** A basement floor drain backup is often caused by a main sewer restriction, root intrusion, or a municipal surcharge during heavy rain. Service focuses on stopping the backup, clearing and inspecting the line, and then recommending targeted repairs or flood-prevention upgrades to reduce repeat events. If you need **Basement Floor Drain Backup Service** in Toronto & the GTA, we’ll start by confirming the real cause, then walk you through the most practical options (quick fix vs long-term fix). To book service, call **647-784-8448** or email **[email protected]**.