Last Updated 07/22/2026
Excerpt from Snohomish Stormwater Ordinance
Chapter 15.16 STORMWATER MANAGEMENT
15.16.065 Best Management Practices (BMPs) Required.
1. Application
Existing development, current activities, and new development activities that are not listed in the exemptions of this section are required to apply stormwater BMPs listed in the Department of Ecology Stormwater Management Manual for Western Washington, Volume IV. A BMP not included in this manual may be approved by the responsible official if the proponent demonstrates that it provides equivalent effectiveness. An exemption from the requirement to use BMPs does not provide an exemption allowing prohibited discharges.
2. Implementation
In applying the Department of Ecology Stormwater Management Manual for Western Washington for existing development, the responsible official shall first require the implementation of nonstructural source control BMPs. If these are not sufficient to prevent contaminants from entering surface and stormwater or groundwater, the responsible official may require implementation of structural source control BMPs or treatment BMPs, using AKART.
3. Inspections
The City shall have the ability to inspect private property to monitor for proper implementation of stormwater BMPs pursuant to SMC 15.16.100.
4. Exemptions
The following persons or entities are exempt from the provisions of this section unless the responsible official determines the alternative BMPs to be ineffective at reducing the discharge of contaminants or activities are causing a prohibited discharge:
1. Persons implementing BMPs through another federal or state regulatory or resource management program; provided the responsible official may perform inspections to ensure compliance with this chapter. If the other program requires the development of a best management practices plan, the person shall make that plan available to the City upon request;
2. Persons engaged in forest practices regulated under WAC Title 222, except for Class IV general forest practices as defined under Chapter 222-16 WAC; and
3. Persons conducting normal residential activities at property containing a single-family detached dwelling, duplex or triplex and modifications to it on a lot approved for such use, unless the responsible official determines that these activities pose a hazard to public health, safety or welfare; endanger any property; or adversely affect the safety and operation of City right-of-way, utilities, and/or other property owned or maintained by the City. (Ord. 2440, 2022)
15.16.070 Construction and Maintenance of Stormwater Facilities.
A. All stormwater facilities required under this chapter shall be constructed and maintained as set forth in the Stormwater Manual and the permits and/or approvals of the City.
B. Maintenance of private stormwater facilities.
- The person or persons holding title to the property and the applicant required to construct a stormwater facility shall remain responsible for the facility’s continual performance, operation, and maintenance in accordance with the standards and requirements of the Stormwater Manual, this chapter, and the permits and/or approvals of the City and shall remain responsible for any liability as a result of these duties. Language designating the responsible parties shall be printed on the face of the plat documents. The requirements of this subsection B shall apply to all new facilities constructed in the City.
- The City shall have authority to periodically enter upon the property and inspect the facilities to ensure such compliance and to issue orders requiring maintenance and/or repair. In event that the titleholders or other responsible parties do not effect such maintenance and/or repairs, the City may perform such work, and the cost thereof shall be recoverable by the City from said titleholders or other responsible parties and/or by filing a lien against the property.
- When an inspection identifies an exceedence of the maintenance standard, maintenance shall be performed in accordance with the following schedule:
– Within 1 year for typical maintenance of facilities, except catch basins.
– Within 6 months for typical maintenance.
– Within 2 years for maintenance that requires capital construction of less than $25,000.
15.16.100 Inspection
1. The Director is authorized to gain access to private property as provided by law and in this chapter, to make such inspections of stormwater facilities or source control BMPs, and take such actions as may be required to enforce the provisions of this chapter.
2. Inspection prior to clearing and construction will apply to sites with a high potential for sediment damage, as identified by the applicant during civil review based on definitions and requirements of Appendix 7 of the Western Washington Phase II Municipal Stormwater permit.
3. Whenever necessary to make an inspection to enforce any of the provisions of this chapter or to monitor for proper function of stormwater facilities, or whenever the Director has reasonable cause to believe that violations of this chapter are present or operating on a subject property or portion thereof, the Director or a designee may enter such premises at all reasonable times to inspect the same or perform any duty imposed upon the Director by this chapter; provided, that if such premises or portion thereof is occupied, the Director shall first make a reasonable effort to locate the owner or other person having charge or control of the premises or portion thereof and request entry. If after reasonable effort, the inspector is unable to locate the owner or other person having charge or control of the premises or portion thereof and has reason to believe an imminent hazard exists, the inspector may enter.
4. Property owners shall provide proper ingress and egress to any stormwater facility to the Director or a designee to inspect, monitor, or perform any duty imposed upon the Director by this chapter. The Director shall notify the responsible party in writing of failure to comply with this access requirement. Failing to obtain a response within seven (7) days from the receipt of notification, the Director may order the work required completed or otherwise address the cause of improper access. The obligation for the payment of all costs that may be incurred or expended by the City in causing such work to be done shall thereby be imposed on the person holding title to the subject property and/or imposed against the subject property by filing a lien.
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Frequently Asked Questions
Who is responsible for stormwater maintenance in Snohomish?
Both the person holding title to the property and the applicant who was required to construct the stormwater facility share responsibility for its ongoing performance, operation, and maintenance. This means that even after a property changes hands, the original responsible party may retain some liability, and the new owner takes on the same obligations upon acquisition.
For subdivisions and plats, the responsible parties are identified directly on the face of the plat documents. If you recently purchased a property and are unsure whether this language was included or what it says, that is worth confirming before the City identifies a compliance gap. AQUALIS can manage your stormwater maintenance obligations on your behalf.
How do I know if my Snohomish stormwater system is at risk of failure or safety violation?
Watch for these warning signs.
Catch basins not recently serviced. Snohomish requires catch basin maintenance within six months of an identified deficiency, which is shorter than most other typical maintenance timelines. If yours have not been cleaned recently, they are likely your most immediate compliance gap.
Water is not draining after rain. Standing water more than 72 hours after a storm suggests your system is not functioning as required under the City’s Stormwater Manual.
Visible sediment, debris, or blockages. Buildup around inlets, outlets, or in detention areas is a sign maintenance is overdue and puts you at risk during a City inspection.
You cannot provide access for inspection. Failing to respond to the City’s written notice within seven days is itself a violation that can trigger cost recovery and a lien. If an inspector has contacted you, respond promptly.
Recent property purchase. Snohomish requires that responsible party language be printed on plat documents, but the obligations transfer with the property regardless. If you recently bought a commercial property and are unsure what stormwater facilities exist or what maintenance is required, an AQUALIS assessment can give you a clear picture before any issues become your liability.
How quickly does Snohomish require stormwater maintenance to be completed?
Once an inspection identifies that a maintenance standard has been exceeded, Snohomish sets firm deadlines based on the type of work needed.
Six months for catch basin maintenance.
One year for all other typical facility maintenance.
Two years for maintenance that requires capital construction under $25,000.
If you do not complete the required work within these timelines, the City can step in, perform the work itself, and recover all costs from the property owner. The City can also file a lien against your property to collect those costs.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
