Middleton, WI Environmental Rules: Stormwater Management (2026)
Key Facts
- Permit trigger
- 20,000 sf new impervious / 4,000 sf redevelopment
- Sediment reduction
- 80% new / 40% redevelopment
- Infiltration standard
- 90% of predevelopment volume
- Review period
- 60 calendar days, silence = approval
- Financial guarantee
- Required over $5,000 practice cost
- Appeals to
- Water Resources Management Commission
Summary
Middleton requires a Storm Water Runoff Control permit for new development that creates 20,000 square feet or more of impervious surface, or redevelopment disturbing 4,000 square feet or more, and mandates an 80 percent sediment-load reduction for new development under Chapter 26.
1.New development that results in the creation of new impervious surface area that equals or exceeds twenty thousand (20,000) square feet.2.Redevelopment that involves a land disturbance, impervious or otherwise, that equals or exceeds four thousand (4,000) square feet. ... 1.For new development, practices shall be designed to reduce by eighty (80) percent the total suspended solids load within storm water runoff based on the average annual rainfall record, as compared to no runoff management controls.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 3 Update 1).
Full Breakdown
Chapter 26, readopted by Ord. No. O1653 on April 1, 2025, requires a Storm Water Runoff Control permit for any subdivision plat or certified survey map, and for land development creating 20,000 square feet or more of new impervious surface, or redevelopment disturbing 4,000 square feet or more (Section 26.04(1)). On-site practices must reduce total suspended solids by 80 percent for new development and 40 percent for redevelopment, measured against no controls (Section 26.06(1)(a)). Parking lots and other oil-prone sites must treat the first half-inch of runoff for oil and grease (Section 26.06(1)(b)).
New development must also maintain post-development infiltration volume at 90 percent of predevelopment volume, capped at an effective infiltration area of 2 percent of the site unless a partial fee is paid in lieu (Section 26.06(3)(a)). Storm water ponds must stay at least 100 feet from a private well and 400 feet from a municipal well (Section 26.06(1)(e)). The City Engineer reviews complete applications within 60 calendar days, and failure to respond within that period is deemed approval (Section 26.10(2)). Financial guarantees are required whenever storm water practice costs exceed $5,000, capped at construction cost plus 25 percent (Section 26.10(6)). Appeals of the City Engineer's decisions go to the Water Resources Management Commission within 30 calendar days (Section 26.12(2)).
Violations & Fines
Noncompliance found during a required inspection, held at least every 30 days during construction, triggers written notice and a 24-hour deadline to begin corrective action (Section 26.11(3)). Missing that deadline brings a stop work order, permit revocation, and City remedial work billed to the owner as a special charge under Wis. Stat. Section 66.0627. Violators also face a forfeiture under Section 30.04 and injunctive action under Wis. Stat. Section 62.23(8).
Frequently Asked Questions
What size project triggers a stormwater permit in Middleton?
How much sediment reduction does Middleton require?
What if the City Engineer never responds to my application?
Sources & Official References
Other rules in Middleton
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Stormwater Management in Nearby Cities
How other cities in Dane County handle stormwater management.