Rear Yard Drainage & Engineering

Drainage & Flooding

The Village is committed in mitigating storm water flooding on public and private property. In older communities some of the storm sewer infrastructure is undersized to convey the large amounts of storm water runoff associated with rain events and continued development within the Village. La Grange Park like most nearby communities has a combined sewer system, which means both storm water and sanitary waste from homes are conveyed through the same pipe. Two major concerns with combined systems are reduced capacity and the occurrence of sewer backup in basements.

Restricting Water Flow

One way the Village approaches high flows during rain events is by attempting to restrict storm water flow from private residences into the Village storm sewers. This allows for the streets to drain first without overwhelming the storm sewers with storm water runoff from private property. The Village has taken steps to ensure private property storm water connections are eliminated through the Downspout Disconnection Program. Also when retro fit drain tile is installed in a home the sump pump must discharge to the yard and not the sanitary sewer.

In addition to restricting flows to the sewer system the Village instituted the Sewer Backup Prevention Program. This program which has been in place for three years provides 50% reimbursement of eligible sewer related costs, subject to a maximum reimbursement of $3,000 for backflow devices or $5,000 for overhead sewers.

Rear Yard Flooding

Rear yard flooding is another common issue within the Village. There have been several key steps to help mitigate rear yard flooding hazards. The zoning code requires minimum amounts of green space for each property in town. In the most common zoning district buildings such as homes and garages can only coverage a maximum of 30% of the lot area, maximum building coverage. In addition all residential properties are restricted to a maximum of 50% impervious surface coverage for all non-porous surfaces such as driveways, patios and buildings. 

The Village also adopted the Storm Water Ordinance to require site engineering for developments and topographically changes to existing properties which requires a variety of actions by the developer or owner. Projects such as additions, driveways and patios larger than 250 square feet are subject to the requirements of this ordinance. The ordinance requires a site grading plan and storm water calculations submitted by a licensed civil engineer, most projects require on-site detention within the property. Detention areas for new improvements shall provide storage for a 3 inch rain event through dry-wells, rain gardens, infiltration trenches, or other approved means. All plans are reviewed by the Village Engineer for compliance with Village Ordinances and sound engineering practices.

Additional Information

View the Back Yard Flooding - Help Guide (PDF) for more information on rear yard flooding and ways to manage the issue.