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Watershed Protection and Restoration Fee FAQ's

What is the Watershed Protection and Restoration Fee?
The Watershed Protection and Restoration Fee (WPRF) is a state law-mandated stormwater remediation charge assessed to Anne Arundel County property owners based on the amount of impervious surface on their property to provide Maryland's largest jurisdictions an infusion of revenue to support the pollutant-reducing waterway capital improvements required by the state and federal governments.
The WPRF appears as a line item on Property Tax Bills.
Why is the Watershed Restoration and Protection Fee needed?
State law mandates Maryland's largest jurisdictions assess stormwater remediation fees to property owners to fully fund the State/Federal government-required projects that reduce the amount of pollutants associated with runoff in the Bay.
Anne Arundel County must also cover the capital project expense required to meet the Environmental Protection Agency's (EPA) Chesapeake Bay Program's pollutant-reducing goals for a swimmable and fishable By by 2025. 
Counties must cover the extraordinary cost to meet their stormwater management infrastructure obligations as regulated and required by the National Pollutant Discharge Elimination System (NPDES) Phase I Municipal Separate Storm Sewer System (MS4) permit.
All 12 major County waterbodies are impaired by two or more pollutants and fail to meet federal Clean Water Act standards.
How will the County use the revenue generated by the WPRF?
The County, by law, must use revenue generated by the WPRF to:
  • Provide sufficient funding for projects that meet the the required Chesapeake Bay pollutant-reducing goals of the EPA's Chesapeake Bay Program.
  • Provide sufficient funding to meet the stormwater management infrastructure obligations regulated by the NPDES MS4 permit. 
The County, by law, may not:
  • Use revenue to fund any non-stormwater related purposes.
  • Transfer revenue to the General Fund.
Identified projects that meet operating and capital improvement obligations associated with the County's MS4 Permit and the pollutant reduction goals of the EPA's Chesapeake Bay Program by 2025 include:  
Stormwater Management Capital Improvement Projects
Nitrogen and Phosphorous-Reducing Stream/Wetland Restoration Projects
Public Education and Outreach Relating 
Projects to Meet Existing Stormwater Managment Permit Obligations
Local stormwater management planning, including:
  • Mapping/assessment of impervious surfaces.
  • Monitoring, inspection and enforcement efforts to carry out the program.
  • Review of stormwater management plan/permit applications for new development provided existing charges/fees collected are deposited into the fund.
How was the impervious surface area determined for residential and non-residential properties?
The Anne Arundel County Department of Public Works utilized state-of-the-art Geographic Information Systems (GIS) technology along with parcel data collected from the Consolidated Property File and County Zoning Maps to estimate the imperviousness of residential properties.  GIS technology and aerial photography was used to actually measure the impervious surface area for non-residential properties.
What is the annual residential rate?
Annual Residential WPRF Rates
Zone CalculationYr  1Yr  2WPRF
R10One (1) ERU x 0.4$20.40$27.20$34
R15One (1) ERU x 0.4$20.40$27.20$34
R22One (1) ERU x 0.4$20.40$27.20$34
R1One (1) ERU $51$68$85
R2One (1) ERU$51$68$85
R5One (1) ERU$51$68$85
RAOne (1) ERU x 2$102$136$170
RLDOne (1) ERU x 2$102$136$170
Base rate is $85 for each Equivalent Residential Unit (ERU) (2,940 sq. ft. of imperviousness).
An ERU equals 2,940 sq. ft. of impervious surface.
Three separate billing tiers represent properties in residential zones with estimated imperviousness that have less, equal or a greater amount of impervious surface than the base ERU of 2,940 square feet (see box below).

ZONING DISTRICTS R1, R2 and R5: Assessed one ERU based on estimated imperviousness of 2,940 sq. ft.

ZONING DISTRICTS R10, R15 and R22: Assessed one ERU x 0.4 based on estimated imperviousness that is 40% of the base ERU of 2,940 sq. ft.

ZONING DISTRICTS  RA and RLD: Assessed one ERU x 2 based on estimated imperviousness that is two times the base ERU of 2,940 sq. ft.   

What is the rate for non-residential properties and how is it calculated?
Nonresidential properties are also assessed at the base rate of $85 for each ERU (2,940 sq. ft. of imperviousness). However, these properties are assessed based on the parcel's actual measured impervious surface.    The rate structure for non-residential properties is calculated based on the following:

►The total square feet of imperviousness DIVIDED BY 

►base ERU of 2,940 square feet MULTIPLIED BY

►base ERU Rate of $85.


  • A property with 29,400 square feet of impervious surface will be charged 10 times the base rate or $850.  
  • 29,400 / 2,940 = 10 (# of ERU's; 10 x $85 (Base Rate) = $850
  • Generally, non-residential fees are capped at 25% of their nominal State and County real property tax assessement prior to any tax credits, deferrals or exemptions.
  • Non-residential fees greater than $500 are phased in at 60% of assessment in year one and 80% in year two. 
Can I appeal my WPRF assessment?
Yes.  Property owners that feel their bill was assessed or calculated incorrectly may appeal their bill to the Department of Public Works.  Administrative appeals will be based on the following criteria:
  • Incorrect Zoning Classification of Real Property
  • Errors in Impervious Area Calculation for Non-Residential Property
  • Mathematical Errors in Calculation 
  • Real Property is Not Subject to the Charge
  • Property Owner is Exempt From the Charge
  • Errors in the Identification of the Property Owner

The deadline to appeal your WPRF assessment is September 30 for each taxable year.

Is there a deadline to file an appeal?
Yes.  The County Code stipulates the deadline to file an appeal is September 30.
Do I have to pay the fee if I file an appeal?
If you file an appeal, you are not required to pay the Stormwater Remediation Fee for the tax year the appeal was submitted until a decision is rendered.  If your appeal is upheld, you will receive a new bill for the Stormwater Remediation Fee.  If your appeal is denied, you will be required to pay the originally billed fee.  
How long will it take to rule on my appeal?
The Director of Public Works is required to rule within 45 days of receipt of your appeal.  You will be notified of the results of your appeal in a letter from DPW.  If appeal is upheld, a new and revised bill will be issued by the County.
If my appeal is approved, do I have to file a new appeal each year?
No.  The appeal decision will be reflected on the following years’ bills.
Where can I find out the zoning for my house?
A zoning map viewer is available in the "My Anne Arundel" feature on the County's homepage.  
What happens if I don't pay or I pay late?
Unless you have sumbitted an appeal, bills not paid on time may result in late fees or other charges. Unpaid bills may result in a lien against an owner's property.  Depending on certain conditions, properties with attached liens are subject to the County's tax sale.  
Are credits available for improvements to my property that reduce my contribution of pollutants related to stormwater runoff?

There are actually two county programs designed to allow property owners to request monetary credits for stormwater management improvements which have been implemented on their properties.

Stormwater Management Property Tax Credit Program

This is an existing program administered by the Office of Planning and Zoning that provides for a reduction in County Property Taxes for qualified stormwater improvements.  For information and applications, click here

This application must be filled within 45 days after the completion of the qualifying improvements and annually thereafter.

Stormwater Fee Credit Program

This program was developed by the Department of Public Works and, as required by state law, approved by the Maryland Department of Environment (MDE). 

This program recognizes the significant stormwater control investments made by certain property ownwers and encourages runoff control practices that proactively and sustainably manage stormwater on private property.

Stormwater Fee Credit Program Information 

Stormwater Fee Credit Program and Policy Document for Anne Arundel County

Stormwater Fee Credit Program Applications

What should I do if I received a WPRF bill for a property I no longer own?  

If you are not the current owner of the property, you are not obligated to pay the WPRF.


The WPRF assessments were sent from a list of property owners provided to Anne Arundel County by the Maryland State Department of Assessments and Taxation (SDAT).  The error in ownership originates in their records. 


Please submit Form 13-5 "Exempt or Incorrect Property Owner"  to indicate that you are not the current property owner.  In addition, you will need to personally contact SDAT (see below) to request the property information be updated.  Once verified, you will not receive bills in the future.


Maryland SDAT

Anne Arundel County 


My Homeowner's/Community Association-owned property was assessed a WPRF for a common area or right-of-way that has no impervious surface area?  
DPW has become aware of  multiple instances around the County where neighboring property owners have encroached into Open Space or Recreational Areas owned by Homeowenrs Associations.  These typically involve sheds or portions of driveways which extend beyond the private property lines into the community owned property.  In calculating the WPRF, these impervious surfaces appear to be part of the community association property and as a result, get billed to the community association.
If you feel that the bill for your community association or HOA shows more impervious area than it should please file an appeal on Form 13-4 "Mathematical Error or Incorrect Impervious Calculation."  When filling out the form, please check the box next to "Mathematical Error" and provide a brief explanation of the problem.
My residential property is not zoned within the three residential billing tiers.  How was my property assessed the WPRF?

Properties within Residential Zoning Districts are assessed a WPRF based on the median impervious area of all properties within that Tier at a rate of $85 for every 2,940 square feet of impervious area. The rates for each Tier are as follows:


Residential Tier

Estimated Impervious Area (sq. ft.)

100% WPRF

2nd Year Phase-in (80%) WPRF

Tier 1


$ 170.00

$ 136.00

Tier 2


$  85.00

$   68.00

Tier 3


$  34.00

$  27.20



Residential properties that fall outside of a Residential Zoning District, for example in Commercial, Industrial or Marine Zoning; are assessed at the same rate as the residential properties in Tiers 1, 2 and 3 ($85 per 2,940 square feet of impervious area).  However, the WPRF for these properties is based on the actual calculated impervious area of their individual property.


Property owners may view their zoning districts on the digital map “Anne Arundel County Digital Zoning Layer” prepared by the Office of Planning and Zoning and adopted by the County Council. 


For more information regarding the zoning process, visit the Office of Planning and Zoning webpage

I submitted my stormwater remediation fee credit application prior to the April 30, 2014 deadline.  Why doesn't my 2015 tax bill include the credit?

The credit applications are currently under review. Once a decision has been rendered, the Department will instruct the County’s Office of Finance to make any necessary adjustments to the stormwater remediation fee and issue a revised bill and/or refund. Because your credit was submitted before the April 30, 2014 deadline, any fee adjustments resulting from your credit will also apply to the 2014 stormwater remediation fee.

For additional information on the Credit Program please visit the “SWF Credit Program Information” page. 



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Anne Arundel County, Maryland. 44 Calvert Street, Annapolis, Maryland 21401 | Tele: (410) 222-7000