By Casey Thomas, GIS Analyst, Philadelphia Water Department

Published on March 6, 2008
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The Philadelphia Water Department (PWD) has been financing its stormwater management through a sewer-service charge since 1968, but it will soon change the way it charges its customers by creating a separate stormwater utility fee. This proposed fee will be phased in over three years, beginning sometime in 2009.

Storms of increasing intensity, combined with stringent state and federal regulations, are resulting in escalating costs related to the management of stormwater runoff. As a result, cities and municipalities around the country have begun instituting stormwater utility fees. This revenue is necessary to ensure there is a direct source of funds for the provision of stormwater services.

Currently, customers are charged based on the size of their water meter. While this method is appropriate in some cases, it is often not representative of true stormwater costs, and this presents an equity problem.

The PWD will now relate a property’s stormwater management fee directly to its burden on the sewer system by using property characteristics as the basis for this fee. It will do this by using Geographic Information Systems technology, or high-tech mapping software, to measure a property’s gross area and impervious area. Impervious area is classified as any surface that prevents water from soaking into the ground.

In addition to making customers more aware of their impacts and the importance of stormwater management, there are several advantages to this new billing method:

• It is more equitable. Customers who are responsible for generating runoff will be charged accordingly.

• Properties that are currently not customers (i.e., parking lots and others without water or sewer service) will now be charged a stormwater fee since they contribute runoff. This expands the customer base and spreads the cost of service among more people, thus lowering rates.

• It encourages “green” development. Non-residential property owners who are adversely affected by this change can receive credits toward the stormwater portion of their bills if they find ways to reduce stormwater runoff on their properties. Some exemplary ways of doing so include green roofs, porous pavement and infiltration systems, just to name a few.

The PWD is planning its credit system to reward green practices more so than “concentrated” systems, such as underground storage tanks that don’t provide as much infiltration. Once environmentally friendly practices are in place, less stormwater will enter the city’s sewer system. In the long run, this will mean lower costs (or at least slower increases in costs) for stormwater service and lower bills for customers.

Preventing runoff also means good news for the Delaware Estuary. As water makes its way into storm drains, it picks up pollutants like motor oil and bacteria off the streets. During large storm events, much of this gets discharged into rivers before it can be treated. The green practices encouraged by the PWD would not only reduce this runoff, but also they would improve its quality by absorbing and treating these pollutants via vegetative systems. In other words, this program should result in less pollution being discharged and, therefore, a healthier Estuary.

In summary, a revised stormwater fee will result in a fair charge that provides incentives for non-residential and stormwater-only customers willing to pursue green building practices. In addition, all customers will be more aware of the impact they have on the environment and the importance of urban stormwater management.