Nampa, ID Environmental Rules: Stormwater Management (2026)
Key Facts
- Governs
- MS4 storm drain system
- Enforced by
- Public Works Department
- Appeal window
- 10 days from notice
- Unpaid abatement cost
- becomes property lien
- Legal basis
- NPDES permit / Clean Water Act
Summary
Nampa bans dumping pollutants into its municipal storm drain system and enforces the city's federal NPDES stormwater permit through Public Works inspections, notices of violation, mandatory best management practices, and cleanup of illicit connections.
No person shall discharge or cause to be discharged into the municipal storm drain system or watercourses any materials, including, but not limited to, pollutants or waters containing any pollutants that cause or contribute to a violation of applicable water quality standards. The commencement, conduct or continuance of any illegal discharge to the storm drain system is prohibited except as described as follows...
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 16 Update 1).
Full Breakdown
Nampa City Code chapter 8-4 regulates the municipal separate storm sewer system (MS4) to meet its NPDES permit. It bars discharging pollutants or making illicit connections into storm drains or watercourses, with limited exemptions like irrigation runoff and dechlorinated pool water. The Public Works Department administers the chapter, can inspect industrial and construction sites, require monitoring equipment, and suspend MS4 access during an actual or threatened hazard. Violators get a written notice of violation with a compliance deadline; unremediated violations let the city abate the problem and bill the property owner.
Violations & Fines
Public Works issues a written notice of violation with a cure deadline; unresolved violations can bring city abatement billed to the owner as a property lien, MS4 access suspension, injunctive relief, and liability payable over up to 12 installments.
Frequently Asked Questions
Can I wash my car in the driveway in Nampa?
What happens if I ignore a storm drain violation notice in Nampa?
Sources & Official References
Other rules in Nampa
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