Stormwater Management

 What is the Maryland Stormwater Fee?

In 2012, the Maryland State Legislature passed a law which mandates that the 10 largest jurisdictions in the State create a Maryland Stormwater Fee by July 1, 2013. The Stormwater Fee is a service fee like water, sewer, gas, and other vital utility services. The purpose of the fee is to provide a sustainable dedicated revenue source for maintaining, operating, and improving the stormwater management system, including installing practices to improve stormwater quality. In 2015 the Legislature changed the law to give the City and counties the option to fund their stormwater programs through a dedicated fee or by other means, provided they can prove that their programs are funded sufficiently to meet the requirements of their stormwater permits. The City will continue to fund it stormwater program through the fee.

Who will be charged this fee?
All properties outside of the right-of-way (public streets) will be charged a stormwater fee, including:

  • Residential properties
  • Commercial and Industrial properties
  • Non-profit organizations
  • Religious organizations
  • Private schools
  • Private colleges/universities
  • Federal properties
  • Parking lots
  • Vacant properties

The State law which mandates the Maryland Stormwater Fee specifically exempted properties owned by the State and local governments.

What is the fee for single-family residential customers?
Baltimore has a three-tiered flat rate structure for single-family properties (SFP) parcels based on impervious surface.


Flat Fee

< 820 sq. ft


820 – 1,500 sq. ft.


> 1,500 sq. ft.


What is an impervious surface?
It is a surface that is paved or covered in some way that does not allow water to soak through it and into the earth. Impervious surfaces are constructed surfaces, such as rooftops, sidewalks, roads, and parking lots covered by materials such as asphalt, concrete, brick, and stone.
What is the fee for all other properties? All non-SFPs will be charged based on a calculation of impervious surface: $5/ERU/month. The only exception is the structures of religious non-profits, which will be billed at $1/ERU/month.

What is an ERU?
An ERU stands for Equivalent Residential Unit, which is defined as a weighted median impervious surface area as measured in a representative sample of single-family residential properties within the City. In Baltimore, one ERU is equivalent to 1,050 square feet (sq. ft.) of impervious surface area.

How is the fee calculated for all non-SFPs?
The impervious surface within a property is measured. The number of ERUs is calculated and rounded to the nearest whole number. See the example below:

Property size=

7,000 sq. ft.

Impervious Surface=

6,720 sq. ft.

ERU calculation =

6,720 sq. ft. = 6 ERUS

  1 ERU =

1,050 sq. ft.

Non- SFP Rate =


Base Fee=




All non-SFPs will be charged a minimum of 1 ERU

How will I be billed this fee?
The fee is included in your monthly water utility bill. It is listed as a single line item as "stormwater fee."

What if my property does not receive water service?
A separate "stormwater only" bill will be sent to you on a monthly basis.

Is there any way to decrease my fee?
Customers may earn credits against their fee by removing impervious surface from their property, or adopting best management practices like installing rain gardens or planting trees. Single- family properties may also earn credits by participating in organized clean ups or other approved activities.

Are SFP customers eligible for senior and/or low-income discounts?
Yes, customers already approved for senior citizen or low-income discounts for water/wastewater bills will automatically receive a discount for their Maryland Stormwater Fee.

What is stormwater?
It is simply any water that comes in contact with or collects on the ground. Stormwater includes rain water runoff, snow melt, or other waters that flow to streams, wetlands and other water bodies such as our reservoirs and the harbor.

How is stormwater "managed?"
Historically, stormwater management diverted rain water and existing streams into pipes or open channels to keep it away from streets and properties, and to prevent flooding. These strategies managed the amount of water flowing through an area, but did nothing to make the water cleaner. Stormwater management now includes new best management practices (BMPs) to remove or keep pollutants out of the water entering our storm drain systems, and to slow the water so it does less damage as it flows.

What is the City's role in stormwater management?
The Department of Public Works (DPW) operates and maintains the City's system of 1,146 miles of storm drain pipe; 52,438 inlets; 27,561 manholes; 1,709 outfalls; four storm water pumping stations; and 5 large debris collectors. Under the new Stormwater utility, DPW will protect, enhance and restore watersheds by implementing BMPs throughout the City to improve the quality of water in our streams, harbor and Chesapeake Bay. These activities are required by the Environmental Protection Agency (EPA) through the National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm System (MS4) permit for the City's public storm drain system.

How had the City paid for stormwater management?
Historically, money from the City's General Fund (property taxes and gas taxes) funded stormwater operations and capital improvements. However, this funding source is used for many other City programs and has not been adequate to keep up with improvements to and maintenance of the storm drain system, nor are they able to fund the improvements required by federal laws to reduce pollution and make our surface waters cleaner.
What will the Maryland Stormwater Fee pay for? The Maryland Stormwater Fee will provide funding for the following:

  • Complying with the MS4 Permit, including monitoring and code enforcement related to stormwater management and erosion, and sediment control;
  • Implementing best management practices (BMPs), including rain gardens;
  • Repairing, replacing and improving the City's stormwater infrastructure;
  • Maintaining operations for both storm drain infrastructure and BMPs; and
  • Faster reviews of developers' stormwater plans.

How much revenue is anticipated from this fee?
The proposed rate structure will yield about $24 million annually in revenue.

Will the fee increase?
The SFP tiers and the $5/ERU/month fee for non-SFPs fee will remain stable at least through Fiscal Year 2017.

What is a stormwater utility and how is it different from the Maryland Stormwater Fee?
The utility is an enterprise fund that protects the revenues collected from the Maryland Stormwater Fee. It provides:

  • A more equitable system: Contributors to stormwater runoff share based on a metric directly connected with the service provided.
  • A stable level of funding: Ensures that stormwater management receives adequate support, independent of the City's tax rate and General Fund.
  • A dedicated fund: Revenues are used solely for stormwater management purposes. This also allows the City to sell bonds which will keep rates stable for longer.

How can I find out more information?
You can request more information by calling 410-396-5398, or e-mailing