Floodwater in a garage or slab-on-grade room

How water gets in, and where it goes next

On many hillside lots the driveway descends from the street to the garage. In a cloudburst, the street gutter can overflow and the driveway becomes a channel pointing directly at the overhead door. A trench drain across the driveway helps only if it is clear and has capacity. The weatherstrip at the bottom of the overhead door stops wind and light rain, not moving water.

Garage slabs are typically set a step lower than the house floor, which protects the house in small events. In a larger one, water rises to the threshold of the entry door and flows into whatever room is on the other side, often a mudroom or laundry room built on its own slab. Those rooms usually have drywall, cabinets and sometimes vinyl or laminate flooring directly on concrete, all of which react badly to contaminated water.

If chemicals were stored at floor level, the floodwater in the garage may carry a sheen or smell. Avoid skin contact, ventilate, and do not send that water into a floor drain that might connect to the sanitary sewer. Ask the Town of Castle Rock or Douglas County about proper disposal of chemical-contaminated debris.