How Heavy Rainfall Affects Sewer and Drain Lines

In the Chicago suburbs, downpours can move faster than stormwater systems were designed to handle. When heavy rainfall hits, sewer and drain lines can become overwhelmed, leading to surcharging (water backing up in pipes), street flooding, and in some cases sanitary sewer backups into basements.

While most residents know that “a lot of rain” is a problem, the mechanism is more specific: stormwater and wastewater flows can exceed pipe capacity, hydraulic pressure can rise, and water can find pathways into homes or low-lying areas—especially when drains and inlets are blocked or when the ground is already saturated.