Kirkwood, MO Environmental Rules: Stormwater Management (2026)
Key Facts
- Permit trigger
- 1,000+ sq ft new impervious area or 25%+ lot coverage
- Capture standard
- First 1.14 in. of rainfall runoff, § 5-202(a)(1)-(2)
- MSD review required
- Projects one acre or larger, or any commercial/multifamily project
- Sump pump discharge
- Drywell (10-ft setback) or filter strip (20-ft setback)
- Maintenance agreement
- Recorded with St. Louis County Recorder, § 5-205(a)
Summary
Kirkwood makes larger infill projects capture their own runoff before it leaves the lot. Section 5-202 requires a stormwater permit for any project adding 1,000 square feet or more of impervious area, or pushing total lot coverage to 25 percent or higher, and both trigger the same numeric treatment standard.
REGULATED INFILL DEVELOPMENT The creation of net additional impervious area of at least 1,000 square feet or causing the total impervious area on the lot to be 25% or greater of the total lot area for commercial, industrial, or residential real property through new development, redevelopment, or rehabilitation of existing lots. ... (a) All regulated infill development shall not proceed without a permit and shall meet the requirements of this section. (1) All regulated infill development creating 1,000 square feet or more of net additional impervious area is required to treat, by means of capture, the first 1.14 inches of rainfall runoff, for impervious area equal to the net additional impervious area. Vacant lots shall be subject to this requirement.
Full Breakdown
Article VII defines regulated infill development in § 5-201 as creating at least 1,000 square feet of net additional impervious area, or pushing a lot's total impervious coverage to 25% or more, on commercial, industrial or residential property through new development, redevelopment or rehabilitation; a vacant lot is measured against the 2001 aerial photography the City keeps on file. 14-inch capture standard, sized to the larger of the excess-over-25% area or the net addition, once total coverage crosses the 25% threshold. Projects already required to provide stormwater BMPs by the Metropolitan St.
Louis Sewer District are exempt from those two capture rules under (a)(3), and any project disturbing an acre or more, or any commercial, industrial or multifamily project regardless of size, must also go through MSD plan review under (a)(4) and (a)(5) before the City issues a building permit. Section 5-203 layers on a separate sump-pump rule: a sump discharge causing a nuisance under § 16-2 must run to a drywell sized for at least 175 square feet of contributing area and set back 10 feet from any property line, or a vegetated filter strip sized the same way but set back 20 feet.
Violations & Fines
Regulated infill development without the § 5-202 permit, or a site whose stormwater BMP falls out of the maintenance agreement required by § 5-205, is enforced under § 5-206 and § 5-207 as a Property Maintenance Code violation, meaning the fine and each-day-separate-offense penalty structure of Chapter 5, Article III applies, and the City can withhold an occupancy permit until the BMP passes inspection.
Frequently Asked Questions
What size project triggers Kirkwood's stormwater rules?
Does Kirkwood exempt projects that already work with MSD?
Where does my sump pump have to drain in Kirkwood?
Sources & Official References
Other rules in Kirkwood
Compare Kirkwood to another location·View the Missouri environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Stormwater Management in Nearby Cities
How other cities in St. Louis County handle stormwater management.