New Stormwater Rate

The second of five scheduled stormwater fee increases will take effect January 1, 2017.  The new rate will be $17.28 per ERU.  These fees pay for maintaining an aging infrastructure and meeting federal clean water requirements.  To learn more about stormwater and the surface water utility, visit our website

What are the Surface Water Rates in Mukilteo?

City of Mukilteo Adopted Monthly Surface Water Utility Rates:

2005-2015        $7.85 per ERU

2016                    $14.84 per ERU

2017                     $17.28 per ERU

2018                    $19.19 per ERU

2019                    $21.20 per ERU

2020                    $23.43 per ERU

The surface water utility fee appears on your Mukilteo Water and Wastewater bill as “City storm water.” A 6% tax also appears on the bill as “City storm water tax.” It is billed every two months.

How Are Surface Water Rates Calculated? What is an ERU?

The surface water rates are calculated based on one Equivalent Residential Unit, or ERU. One ERU equals 2,500 square feet of impervious surface.  Residential properties are billed for one ERU, regardless of actual impervious surface coverage.

Non-residential properties are calculated based on actual square footage of impervious surface coverage. For example, if a non-residential property has 7,500 square feet of impervious surface, they are charged for 3 ERUs (7,500/2,500=3).

How is Impervious Surface Measured?

For non-residential properties, impervious surface calculations are made at the time of site development. Impervious surfaces include any area that restricts rain water from reaching the soil; such as roofs, driveways, parking lots, and gravel areas. The calculations are used to determine how many ERUs are billed for stormwater fees.

Are There Any Credits Available?

Qualifying low-income senior citizens and low-income disabled citizens can receive a 50% discount of the residential rate. If you qualify for a reduction on your Snohomish County property taxes, you qualify for the City’s Surface Water Fee reduction. Contact Permit Services (425) 263-8000 for an application.

Why a Rate Increase Now?

In 2015, the City reviewed the stormwater utility’s needs and the utility rates. While the City has added essential services including street sweeping, outreach programs, additional staff, and stormwater pond retrofits, the utility rates were not covering the costs of these programs.  With a five-year graduated rate increase (beginning in 2016), the City anticipates having the necessary capacity to meet ever-growing needs and requirements.

What is the Right Rate?

In 2014, the City contracted with a qualified consultant to conduct a rate study. The rate study reviewed current costs and anticipated future costs associated with regulatory requirements, several capital improvement projects, and infrastructure assessment.  The City determined that an increase in stormwater utility rates was needed to maintain essential services as well as to fund mandatory regulatory compliance work.  Forty seven capital projects were identified in this process.  To keep rates low, only nine of these projects were scoped as part of the rate study.

How Was the Public Involved?

The public was invited to participate in the process by identifying surface water needs and developing the rate through several avenues, including two Open House events, direct mailings, request for input on drainage issues, a Public Hearing, and a Citizen Advisory Committee. If you would like to be included as a party of interest for future surface water issues, please contact (425) 263-8170.

What is a Surface Water Utility?

A Surface Water Utility is a stand-alone service, responsible for building and maintaining the City’s public drainage system. The drainage system carries runoff from roads and developed areas into natural waterways. This system includes roadside ditches, pipes, detention ponds, catch basins, and storm drains. A Surface Water Utility generates its revenue through user fees, just like the wastewater utility and the drinking water utility.  Revenues from these fees go into a separate fund, to be used only for surface water services.

Surface water services include managing and maintaining infrastructure, providing technical assistance to property owners, providing review of development projects, meeting regulatory obligations, and using best available science to prevent pollution from entering our streams and Puget Sound.

Regulatory Obligations: In addition to providing the essential functions of managing stormwater, the City also has obligations under the National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater Permit.  This permit requires the City to limit pollution that leaves its drainage system.  The NPDES Permit is based on the Federal Clean Water Act, and has been in place in Mukilteo since 2007.

Pollution (Water Quality): Every time it rains, runoff (the rainwater that is not absorbed into the ground or evaporated) carries contaminants from lawns, streets, buildings and parking lots, and deposits them directly into our streams and Puget Sound. Better pollution control and treatment is needed to reduce the pollution flowing into our local waterbodies.

Impervious Land, Localized Flooding, and Landslide Hazards (Water Quantity): The City’s goal is to manage stormwater runoff so that it does not negatively impact our streams, steep slopes, or infrastructure.  With development, there is more impervious area (paved streets, buildings, etc.).  Impervious areas do not allow water to infiltrate, causing increased surface runoff.  The steep slopes and underlying glacial till in Mukilteo combine to present unique challenges for managing frequent and intense rainfall events.

Where Does Our Money Go?

The stormwater fees go towards better stormwater management. Gradually you should see results in terms of better localized flooding management, stormwater maintenance, and regulatory compliance.  Priorities for capital projects and other Utility programs are identified in the Stormwater Comprehensive Plan Update, and re-evaluated as new information is gathered.  The Utility has defined Performance Measures to help evaluate its programs annually.


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