Lake Whatcom Stormwater Utility Frequently Asked Questions

1.   What is stormwater?

Stormwater is water from rain or snowmelt that flows across the landscape to the nearest ditch, catch basin, or stream.  Stormwater picks up pollutants from the surfaces it flows over and carries them downstream to Lake Whatcom. 

2.    What is a stormwater utility?

A stormwater utility is a way for local jurisdictions to collect fees for the control and treatment of stormwater and manage their stormwater system like a water or sewer utility.  Most cities and counties use a stormwater utility to pay for their stormwater system and programs.  No new government entity will be created with the Lake Whatcom Stormwater Utility.  It is simply a new funding source for Whatcom County’s Lake Whatcom Stormwater Program.  

3.    How was the Lake Whatcom Stormwater Utility established? 

Whatcom County Council established the Lake Whatcom Stormwater Utility service area and rates through the legislative process. First, the Lake Whatcom Stormwater Utility Service Area was established through Ordinance No. 2017-076 in December 2017. From June 2018 to March 2019 Whatcom County Public Works conducted a funding study to evaluate rate structure options.  At the end of the funding study, County Council considered the proposed rate structure and approved Ordinance No. 2019.053 in July, 2019.   Visit the Approval Process page for more information.

4.    Why was the Lake Whatcom Stormwater Utility established?

Whatcom County is required to manage stormwater in the Lake Whatcom watershed and reduce stormwater pollution entering the lake. Funding sources for the Lake Whatcom Stormwater Program were not enough to meet water quality improvements required by the Washington State Department of Ecology.  The new stormwater utility was established to provide supplemental funding needed to meet water quality improvements required by the Lake Whatcom Total Maximum Daily Load (TMDL).

5.    What is the TMDL?

The federal Clean Water Act requires states to identify and clean up polluted water bodies.  The Washington State Department of Ecology (Ecology) enforces Clean Water Act rules.  In 1998, Ecology determined that dissolved oxygen levels in Lake Whatcom were too low (a threat to aquatic life) and that some tributaries had too much fecal coliform bacteria (a risk to human health).  This triggered a Total Maximum Daily Load (TMDL) study of the Lake Whatcom watershed.  Findings from this study found excess phosphorus to be the main cause of the lake’s low oxygen problem.  The Lake Whatcom TMDL sets water quality improvement objectives to reduce phosphorus and fecal coliform bacteria entering the lake.  Meeting these water quality objectives will become a requirement of Whatcom County’s National Pollutant Discharge Elimination System (NPDES) municipal stormwater permit in August 2019.  Learn more here.  

6.    Why do we need to reduce phosphorus?

Whatcom County must reduce phosphorus inputs into the lake to meet its NPDES stormwater permit requirements (see FAQ #5). Water quality monitoring data show decreasing amounts of dissolved oxygen in Lake Whatcom.  Dissolved oxygen is necessary for aquatic life and a healthy lake.  Phosphorus is a nutrient for plant growth.  Excess phosphorus entering the lake causes excessive algae growth.  When algae die, the decomposition process removes dissolved oxygen from the lake.  Reducing phosphorus limits algae blooms and maintains healthy dissolved oxygen levels.  

7.    Where does the phosphorus come from?

Phosphorus is an element.  It is essential for all life and a component of rocks and soil.  Any organic matter or soil particle entering Lake Whatcom contains phosphorus.  Phosphorus also dissolves in water, becoming an invisible pollutant.  Common human-generated sources of phosphorus pollution are sediment, yard debris, animal waste, non-functioning septic systems, fertilizer, and detergents.  

8.    Why is the focus on reducing phosphorus from developed areas in the watershed?

Forests naturally recycle much of the phosphorus they produce.  Developed landscapes with hard surfaces and lawns are not able to absorb stormwater and recycle phosphorus to the same extent as a forest, allowing excess phosphorus to runoff into Lake Whatcom.  Phosphorus reductions required by the TMDL and NPDES stormwater permit (see FAQ #5) are based on water quality modeling that estimates a certain level of phosphorus loading from forested areas of the watershed and sets objectives for reduced phosphorus from developed lands only.  Whatcom County must reduce phosphorus runoff from developed areas of the watershed to meet regulatory requirements; therefore, stormwater program activities focus on providing services to reduce phosphorus runoff from developed areas.  

9.    What about other problems and impacts to the watershed?

The Lake Whatcom Stormwater Utility was established by Whatcom County Council to provide supplementary funding for stormwater program expenses needed to meet regulatory requirements from the TMDL and NPDES stormwater permit (see FAQ #5).  Addressing other watershed management issues and impacts is currently beyond the scope of the new utility.  The Lake Whatcom Management Program was established in 1998 by Whatcom County, the City of Bellingham, and the Lake Whatcom Water and Sewer District as a cooperative effort to protect the lake using a long-term management strategy.  Other watershed management issues are addressed through the larger Lake Whatcom Management Program.  For more information visit

10.    How much money will be collected and what will it pay for? 

The amount of money collected through the Lake Whatcom Stormwater Utility will be approximately $820,000 per year. This is the amount of supplementary funds currently needed for Whatcom County to comply with TMDL and NPDES stormwater permit requirements in the following Lake Whatcom Stormwater Program areas: capital project construction, capital project maintenance, outreach and education, homeowner incentives/residential retrofits, water quality monitoring, and administrative costs associated with managing the stormwater utility. Once fully implemented, the utility will provide approximately 25% of the county’s funding for Lake Whatcom management programs.  The remainder will continue to come from other county-wide generated sources and grants.

Lake Whatcom Stormwater 
Program Area
 Additional Annual Program Costs to Cover with the Stormwater Utility
Capital Project Construction
(stormwater treatment facilities)
Capital Project Maintenance  $180,300
Enhanced Outreach & Education  $68,000
Homeowner Incentive Program/Residential Retrofits $200,000
Monitoring  $45,000
Utility Administrative Costs $74,300
Total $817,600

 11.    How was the service area boundary determined and who will pay the fee?

The service area boundary includes all properties that drain to Lake Whatcom outside of the City of Bellingham (i.e., unincorporated areas of the watershed).  Property owners inside the service area will pay the new stormwater utility fee if their property has impervious surfaces like buildings, driveways, and parking areas that do not allow water to soak into the ground.  

12.    Why are only Lake Whatcom watershed property owners outside city limits being asked to pay when everyone benefits from a clean Lake Whatcom?  

Whatcom County pays for its portion of costs related to protecting Lake Whatcom water quality from the Flood Tax paid by all Whatcom County property owners.  Since properties within the watershed have a greater impact on lake water quality than those in other parts of the county, it was determined that those property owners should pay for this additional funding need.  Property owners within the City of Bellingham already pay a stormwater utility fee and a Lake Whatcom watershed protection fee to pay for their portion of Lake Whatcom Stormwater Program expenses, in addition to paying the Flood Tax.

Estimated Current Lake Whatcom stormwater-related cost/year for a house valued at $400,000

City of BellinghamUnincorporated Whatcom County

Stormwater Utility Fee



Lake Whatcom Watershed Land Acquisition and Preservation Program charge
(watershed protection fee)



Flood Control Zone District Tax (Flood Tax)






13.    How were the stormwater utility rates established?

Whatcom County Council appointed a citizen advisory committee to represent rate payers in the Lake Whatcom Stormwater Utility Service Area and advise the council on a recommended rate structure.  County staff and its consultants presented the committee with a range of defensible rate structures.  A proposed rate structure was recommended by the advisory committee to County Council for approval.  It is also consistent with industry best practices and is the most common rate structure throughout the Puget Sound region.

14.    What are the stormwater utility rates?

The rates are based on the amount of impervious surface on a parcel.  Impervious surfaces are hard surfaces likes roofs and driveways that restrict water from soaking into the ground.  Since runoff from impervious surfaces has a greater impact on water quality than runoff from surfaces like landscaping and forest, impervious surface area is used to determine a parcel’s relative impact on water quality. Parcels with more impervious surface area, and thus a greater impact, pay a higher fee. 

Single Family Residences – Fees for single-family residential properties are based on an average impervious area footprint calculated from a sample of residential properties in the service area. There are three rates for small, medium, and large impervious footprint tiers. Property owners may apply for a lower rate with documentation showing the actual impervious area on their property.  Visit the rate adjustment application page for more information.  Read FAQ #16 for an explanation of how single family residential properties were initially assigned an impervious footprint.

Impervious Footprint Tier
Read FAQ #16 for explanation of how properties were assigned to a tier

2020 Annual Charge 
(50% full rate)

2021 Annual Charge 
(full rate)

Small Footprint  less than or equal to 2,500 impervious square feet



Medium Footprint >2,500 – 8,400 impervious square feet



Large Footprint >8,400 impervious square feet



Non Single-Family Residences (all other parcels) – Fees for all other types of properties in the service area will be based on the measured amount of impervious area on the parcel divided by 4,200 square feet, the average amount of impervious area on a typical residential lot or equivalent service unit (ESU, see FAQ #15).  Rates charged will be equal to the single-family residential medium impervious footprint at $73.76/ESU in 2020 and $147.52/ESU starting in 2021.  Annual rates will vary greatly based on the amount of impervious surface on a parcel. 

15.    What is an ESU?

An equivalent service unit (ESU) represents the average impervious area for a single-family parcel within the service area.  The Lake Whatcom Stormwater Utility funding study included measuring impervious area on roughly 150 single-family parcels.  These parcels were randomly selected from a pool of single-family residential parcels that were less than or equal to two acres in size.  Based on the resulting average and median impervious area, it was determined that an ESU of 4,200 impervious square feet was appropriate.

16.    How are single-family residential parcels initially placed in an impervious footprint tier?

There are over 5,000 single-family residences in the stormwater utility service area.  It is not feasible to measure the  impervious area on each of these properties. Instead, impervious area sampling data and parcel size were used to initially place a residential property in an impervious footprint tier. 

Single-family residential properties greater than two acres are all initially charged the “large” impervious footprint rate. Single-family residential properties less than or equal to two acres are initially charged the “medium” impervious footprint rate.  Any parcel smaller than 2,500 square feet will be charged the “small” footprint rate. Impervious measurements from a randomly selected sample of approximately 150 parcels from each group (~300 in total) showed the average “large” lot had significantly more impervious area than the average “medium” lot, which is the primary justification for assessing a higher fee.  

Property owners may apply for a service charge rate adjustment to be reclassified into a smaller impervious footprint rate category based documentation of the measured amount of impervious area on your property. Visit the rate adjustment request page for more information.  

Impervious Tier ThresholdProperties Placed in this Tier
Small footprint: <2,500 impervious square feetAny developed single family parcels less than 2,500 square feet are initially charged the small footprint rate.
Medium footprint: 2,500 to 8,400 impervious square feetAny developed single family parcels <=2 acres are initially charged the medium footprint rate.
Large footprint: > 8,400 impervious square feetAny developed single family parcels >2 acres are initially charged the large footprint rate.

17.    What can I do if I think the fee calculated for my property is incorrect?

Visit the rate adjustment request page for information on the allowed reasons for rate adjustments.  Download a copy of the Service Charge Adjustment Request form from this page for additional details and instructions. 

18.    Can I receive a credit if I have made improvements to manage stormwater on my property?

Property owners who have made improvements that reduce the amount of impervious surface on their property (e.g., installed a pervious pavement driveway that meets County standards) can apply to be charged for a smaller footprint. Properties that have been developed in compliance with the Lake Whatcom Watershed Overlay code (WCC 20.51.420, applies to structures permitted after August 2013) with all runoff managed by a permanent stormwater system may apply for a 35% rate reduction. Visit the rate adjustment request page for more information.  

19.    How will I receive my bill?

The Lake Whatcom stormwater utility annual fee is included as a line item on your property tax statement and is collected by the Whatcom County Treasurer’s Office.  

20.    How do the  rates compare to other similar stormwater fees?  

For most single-family residences, the proposed annual fee is $147.52.  This is comparable to stormwater utility fees in other local jurisdictions and about half of what homeowners in the City of Bellingham pay between their stormwater utility and the Lake Whatcom Watershed Land Acquisition and Preservation Program fees.

21.    Can the money collected be used for other purposes?

No.  All money collected through the Lake Whatcom stormwater utility goes into a dedicated fund within Whatcom County government.  That fund will only be used to cover expenses for the Lake Whatcom Stormwater Program. 

22.   What is the Lake Whatcom Stormwater Utility Capital Facilities Charge?

Capital facilities charges (CFCs) are one-time fees, paid at the time of development, intended to recover a share of the cost of system capacity needed to serve growth. They serve two primary purposes: to provide equity between existing and new customers; and to provide a source of funding for system capital costs. The charge is an upfront charge imposed on system growth and is primarily a charge on new development, although also applicable to expansion or densification of development when such actions increase requirements for utility system capacity.

The CFC applies to the following parcels in the Lake Whatcom watershed:

   Single family parcels that are being developed will pay a flat fee of $1,730.

   Non-single family parcels will pay $1,730 for every 4,200 square feet of impervious area that the development would add to the system.