Surface Water Management Division
Frequently Asked Questions
What is a storm drainage facility?
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A storm drainage facility is any part of an engineered drainage system that collects, conveys, filters, stores, or controls water that flows off your property after a rainfall. Examples include detention ponds, underground vaults, and catch basins. These facilities must be inspected and maintained regularly to prevent flooding, avoid property damage, and protect surface water quality. |
Why is stormwater runoff a problem?
When rain falls on natural landscapes, the water is absorbed and filtered by the soil or taken up by tree and plant roots. In contrast, when rain falls on developed areas, the water rushes across hard surfaces and picks up pollutants such as oil, sediment, fertilizers, and heavy metals. This stormwater runoff flows into storm drains and ditches, and eventually makes its way into rivers, lakes, and Puget Sound. Stormwater runoff is the primary cause of surface water pollution in Washington State. It also causes and contributes to flooding.
Why does Snohomish County require the construction of storm drainage facilities?
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In developed areas, impervious surfaces such as roads, parking lots, and roofs prevent water from soaking into the ground. During a rainfall, these hard surfaces increase stormwater runoff and accelerate its movement into ditches and streams. Often, this results in flooding, property damage, water pollution, erosion, and habitat degradation. Storm drainage facilities help prevent such problems by collecting stormwater runoff, filtering out pollutants, and slowly releasing the water in small amounts. |
Who is responsible for maintaining storm drainage facilities?
Storm drainage facilities serving residential neighborhoods are generally owned in common by all of the homeowners. If the homeowners have a homeowners association (HOA) then the HOA is typically responsible for maintaining their neighborhood facilities. Similarly, the owners of storm drainage facilities on commercial properties or other types of private properties are responsible for maintaining their facilities. Snohomish County currently owns and/or maintains approximately 300 storm drainage facilities. Each year, many of these County-owned facilities are inspected and/or maintained by County crews.
Why did the County create the Drainage Inspection and Maintenance Program?
The program was created in response to the mandates and requirements of the federal Clean Water Act and the associated NPDES permit.
What is the NPDES permit?
“NPDES” stands for National Pollutant Discharge Elimination System. The NPDES permit system, which is part of the federal Clean Water Act, is administered within Washington by the Department of Ecology. In 2007, Ecology issued an NPDES Municipal Stormwater Permit to the larger cities and counties in the state, including Snohomish County. Under the terms of this permit, the County must take steps to prevent pollution from entering and leaving the county’s storm drainage system. These steps include inspecting public and private storm drainage facilities and making sure that facility owners maintain their storm drainage facilities properly.
Why does the County need to inspect my storm drainage facilities?
State and federal laws require Snohomish County to inspect private storm drainage facilities for compliance with the Snohomish County Water Pollution Control Code SCC 7.53. and the Snohomish County Drainage Manual. The main purpose of the inspections is to:
- Check the performance of your storm drainage facilities;
- Identify facilities that need to be cleaned or repaired; and
- Help you understand your maintenance responsibilities.
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Why is it important for me to maintain my storm drainage facility?
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Your on-site drainage facilities were designed to not only collect stormwater runoff at your site, but also to detain stormwater, to slowly release it downstream, and to remove pollutants carried in the stormwater. When you keep your drainage facilities maintained and functioning properly, you benefit your property, the surrounding community, and the environment by:
- Reducing the chance of flooding on your own property;
- Reducing the chance of flooding for downstream property owners and roads that receive runoff from your property;
- Helping to limit the amount of polluted stormwater entering streams, rivers, and Puget Sound; and
- Helping to protect important stream and wetland habitat by limiting high flows that can cause erosion and sediment problems.
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What does the County inspection process involve?
Please see County Inspections of Storm Drainage Facilities.
Will I be charged for the inspection visit?
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No. Surface Water Management (SWM) service charges that are collected throughout unincorporated Snohomish County were increased in 2009 to provide funding for the Drainage Inspection and Maintenance Program and other SWM programs. |
How much will maintaining or repairing my storm drainage system cost?
That depends. Required maintenance activities could include a wide range of actions, from cutting or removing vegetation to excavating accumulated sediment from a detention pond. To determine the cost of the required maintenance work, you should get estimates from one or more licensed contractors.
What will happen after the County inspects my storm drainage facilities?
After the county inspects your facilities, you will receive a letter that tells you what problems or deficiencies were found. You should then get cost estimates from one or more licensed contractors for any maintenance or repair work needed. Based on these estimates, you will be given a time frame for completing the work. For correcting deficiencies in your storm drainage facility, you will normally have 30 days, one year, or two years depending on the type of maintenance work needed and the estimated cost to complete the work. The most common time frame will be one year.
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Are there any penalties for not completing the maintenance or repair work?
Property owners that do not perform needed maintenance and repair work within the time frame required by the County may be found in violation of SCC 7.53, and may therefore be subject to a warning notice, a formal citation, civil or criminal action, and fines of up to $1,000 per day.