The City of Kirkwood is proposing revisions to its Stormwater Ordinance — the set of rules that shape how rainwater is managed across homes, streets, and businesses. The proposed revisions are intended to help the City continue managing stormwater responsibly while supporting long-term community resilience and infrastructure planning.

Before these revisions move forward, we want to hear from residents.

Join Us at the Stormwater Ordinance Town Hall

A public Town Hall on Tuesday, June 30, 2026, from 4:30 to 6:30 p.m. in the Council Chambers at Kirkwood City Hall offers residents, property owners, and community stakeholders the chance to:

• Learn about the proposed ordinance revisions
• Understand how the changes may affect development and property improvements
• Ask questions directly to City staff and leadership
• Share feedback and concerns with City representatives

City staff will provide a short presentation outlining the proposed ordinance revisions at 4:30 p.m. and again at 5:30 p.m. The event is come-and-go — drop in any time during the two-hour window. Members of the Kirkwood City Council will be present, along with Chief Administrative Officer Darren Lamb, Assistant Chief Administrative Officer David Weidler, Assistant City Engineer Jennifer Brown, and Public Services Director Chris Krueger.

What's Proposed 

The proposed revisions update the City's Stormwater Ordinance (Chapter 5, Article VII) and the accompanying Stormwater Manual. The changes are intended to help Kirkwood manage stormwater more effectively as rainfall patterns shift, while protecting neighborhoods from flooding and drainage problems.

The proposed revisions include:

• A lower threshold for requiring stormwater mitigation on new construction and additions, moving from 1,000 square feet of impervious surface down to 500 square feet.
  Maintenance projects — such as replacing a driveway in its existing footprint or rebuilding a dilapidated garage in place — are not subject to this threshold.
• New limits on impervious coverage for residential lots: a maximum of 55% on single-family lots and 85% on multi-family lots. Most of Kirkwood (about 82%) is zoned single-family.
• A grading permit requirement for flatwork — driveways, walkways, sidewalks, patios, and similar improvements — and other impervious additions over 100 square feet that are not already covered by a building permit.
• New requirements for basement depths on new homes and basement extensions, tied to local groundwater conditions. Builders can use either a geotechnical report or the City's Dept to Water Table Map to confirm compliance.
• New rules for sump pump discharge, including a requirement to connect to the public MSD storm sewer system where one is available, and a prohibition on discharging into a stormwater BMP.
• Stronger protections for trees used in stormwater mitigation, including a larger tree credit (raised from 50 to 150 square feet), protections for critical root zones, and replacement requirements if a credited tree is lost.
• Side yard drainage requirements to ensure water moves to the front or rear of properties rather than across neighboring property lines, unless existing drainage patterns are not being altered.
• Other technical updates related to BMP spacing, the use of Stormtech and other MSD-approved BMPs under pavements, and the conditions under which stormwater permit fee refunds may be forfeited.

The full text of the proposed ordinance and manual changes is available in the Proposed Ordinance and Manual Changes document (PDF). City staff will walk through the proposed changes in detail at the Town Hall on Tuesday, June 30.

How the Proposed Stormwater Ordinance Could Affect You

Most Kirkwood residents will see the proposed revisions affect them only when they take on a new project — building, adding to, or significantly changing the impervious surfaces on their property. Like-for-like maintenance, such as replacing a driveway in its existing footprint, is not subject to the new requirements.

What's changing depends on the type and size of the project.

The following is a general guide — the Town Hall on Tuesday, June 30, is the best place to talk through how the proposed revisions might apply to a project you're considering.

If you own a single-family home and are not planning new construction or major additions:

Most of the proposed revisions will not require you to do anything. Routine maintenance — replacing a driveway, repairing a sidewalk in its existing footprint, replacing a fence — is not affected. The new impervious coverage limits (a maximum of 55% on single-family lots) are caps on total coverage rather than triggers for individual projects, and most Kirkwood lots are well under that limit.

If you're planning a home addition, a new patio, a larger driveway, or a similar project:

The proposed revisions establish new thresholds you'll want to be aware of:

• Flatwork or other added impervious area over 100 square feet would require a grading permit if not already covered by a building permit.
• New impervious surface area over 500 square feet would require stormwater mitigation. The current threshold is 1,000 square feet.
• Total impervious coverage over 25% of your lot would require stormwater treatment.
• Single-family lots would have a maximum impervious coverage of 55%.

If you're building a new home or a major addition with a basement:

The proposed revisions introduce limits on basement depth tied to local groundwater conditions, with a path to override via geotechnical report or by referencing the City's Dept to Water Table Map. New sump pump rules would also apply, including required connection to the public MSD storm sewer where available, and a prohibition on discharging into a stormwater BMP.

If you have a property with mature trees:

The proposed revisions strengthen incentives to preserve trees as part of stormwater mitigation, including a larger stormwater credit for qualifying trees and new protections for critical root zones during construction. If a tree credited for stormwater mitigation is lost, replacement is required.

If you're a developer, contractor, or builder working in Kirkwood:

The proposed revisions affect lot-level impervious coverage limits, BMP spacing requirements, basement depth provisions, side yard grading, sump pump discharge rules, and the use of Stormtech and other MSD-approved BMPs under pavements. Refer to the full proposed ordinance and manual for specifics.

The Town Hall is also a good opportunity to discuss implementation questions directly to City staff.

Frequently Asked Questions

This section will be updated as questions begin to come in. Check back for updates.

Accessibility

For accessibility accommodations at the Stormwater Ordinance Town Hall, please contact the City Clerk's Office at 314-822-5802 at least 48 hours in advance.