Stormwater Credits

The Philadelphia Water Department offers incentives to property owners, project managers, and developers to keep and increase stormwater management on their properties while keeping costs down.

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What is the Stormwater Credit Program?

The purpose of the Stormwater Credits Program is to provide non-residential, condominium, and multi-family residential customers the opportunity to reduce their monthly stormwater charge and to provide a financial and environmental incentive for customers to manage stormwater on-site.

Stormwater credits lower a property owner’s monthly stormwater bill. To learn more about how stormwater bills are calculated, or to address a bill you believe to be incorrect, visit the Stormwater Billing page.

The Stormwater Credit Program is one type of Stormwater Incentive offered by the Philadelphia Water Department and managed by the Stormwater Incentive team. For more information, visit the Stormwater Incentives page.

Types of Stormwater Credits

Open Space

For properties that contain areas of natural pervious surfaces that allow water to soak through (such as woods or lawn). The credit amount will vary depending on the soil type, since some soils allow more water to soak in than others.

Impervious Area Reduction (IAR)

For properties that have a downspout or pavement area, such as sidewalk, routed to a grassy or more natural area where the water can soak in. Also for properties that have tree canopy (branches and leaves) over impervious areas such as parking lots or roofs.

Managed Impervious Area (IA/GA)

For properties that manage runoff with stormwater management practices (SMPs, also known as GSI tools), either voluntarily or required by Stormwater Regulations. Also for properties that drain directly to a waterway without using City-owned infrastructure.

NPDES Credit

For properties that hold an active National Pollutant Discharge Elimination System (NPDES) Industrial Permit for industrial stormwater discharge activities. The operator must have been in compliance with the permit requirements during the preceding twelve months.

Many properties are already eligible for one or more types of credits based on the existing conditions of their site. Existing conditions often can provide stormwater credits for open space, IAR, or direct discharge to a waterway with the Managed IA/GA credit. We encourage property owners to consider these options first.

For credits associated with voluntary SMP retrofits, the Stormwater Grants Program can be used for design and construction funding. Check out the Grants page for more information.

Other Resources:

Stormwater Management Guidance Manual

A comprehensive resource for the development community in complying with PWD’s Stormwater Regulations and designing stormwater management on private property.

Private Development Services

A resource for developers, engineers, contractors, and property owners who are seeking information about designing, constructing, or maintaining a property that is applicable to the PWD Stormwater Regulations.

SMP Maintenance Contractor List

A list of Stormwater Management Practice (SMP) maintenance providers that PWD is aware of. This list is neither exhaustive nor an endorsement of any particular company, and other qualified companies may exist in the area.

SMP Maintenance Guidance Manual

Proper maintenance is required to retain stormwater credits for SMPs, and ensures that GSI systems remain effective, beautiful, and safe. The GSI Maintenance Manual describes routine maintenance tasks for SMPs included in PWD’s programs.


If you have any questions about this program, please contact the PWD Stormwater Incentives team at 215-685-6070 or PWD.StormwaterCredits@phila.gov

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