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Source Water Quality and Quantity

Through our Source Water Protection Program, holistic and innovative approaches have been established to address challenges regarding the protection of Philadelphia’s drinking water sources.

Source Water Protection Program

Today, the City enjoys watersheds that are cleaner and healthier than they have been in well over a century. Although we have seen a dramatic improvement in the water quality of the City’s two major rivers since the passage of the federal Clean Water Act in the early 1970s, there is still more work that needs to be done to protect our drinking water sources from pollution. PWD’s Source Water Protection program takes a multi-barrier approach to ensuring the safety and quality of Philadelphia’s drinking water. A holistic approach to water quality has been used since the program’s inception, which occurred in 1999 with the formation of the Office of Watersheds. Over the years, the program has developed a thorough understanding of the City’s water supply characteristics, including ambient water quality conditions, major sources of actual and potential contamination, water availability, flow patterns and management practices, and tidal and reservoir impacts.

The success of the Source Water Protection Program’s organized and comprehensive approach is evident in the integrity of the Delaware and Schuylkill Rivers as drinking water supplies. PWD produces approximately 250 million gallons of high-quality drinking water for its customers on a daily basis through its three drinking water treatment plants. Each river contributes approximately one-half of the City’s overall drinking water supply. In order for the program to continuously meet its high standards, PWD employs a wide range of tools including research projects, regional partnerships, outreach and education, advanced technologies, and on-the-ground implementation and monitoring to achieve, if not exceed, source water goals.

Forming the basis of PWD’s various source water protection efforts are the Source Water Assessment (SWA) and Source Water Protection Plan (SWPP). Completed in 2002, the SWA was created in response to the 1996 Safe Drinking Water Act Amendments, which call for the assessment of all source water supplies across the U.S. to identify potential sources of contamination. PWD, along with its project partners, conducted a watershed-based, multi-phase assessment that identified and prioritized potential and existing sources of contamination and evaluated the vulnerability of the water supply to these contaminant sources. The SWPP establishes a set of priority actions to address threats to the water supply identified during the assessment phase. The plans’ recommended action items are based upon a holistic watershed approach that recognizes the interconnectedness between source water protection concerns, upstream land and water use, and the need to maintain a healthy aquatic ecosystem. Upon completion of the protection plan, PWD became one of the first water suppliers in the state to meet all steps outlined in the Pennsylvania Department of Environmental Protection’s (PADEP) minimum criteria for a Source Water Protection Program.

Explanation of Source Water Protection Issues

Numerous environmental, social and developmental trends materializing in Philadelphia’s watersheds raise watershed resource concerns and pose challenges to the protection of the City’s drinking water sources, the Schuylkill and Delaware Rivers.

Listed below are the source water protection program’s primary concerns related to maintaining a high quality drinking water source for Philadelphia.

Climate Change

Climate change is a change in the statistical distribution of weather over periods of time, ranging from decades to millions of years. In the northeastern United States, climate change has the potential to impact the region’s water supplies in multiple ways. Increased overall precipitation and changes in vegetation could exacerbate stream bank scouring and lead to increased levels of pollutants washing into our waterways. Severe weather could compromise water and wastewater facilities and infrastructure and lead to more frequent spills and accidents. Increased temperatures could foster bacterial growth and substantially decrease the oxygen supply available for aquatic life. Water availability may also become a bigger concern with the potential for climate change to produce more frequent, short-term droughts in our area.

Forest Clearing and Development

Forest clearing miles from Philadelphia to accommodate land development, economic initiatives, such as natural gas drilling, and increasing populations can significantly decrease the quality of our water supply. As an example, if all of the forest in the Schuylkill watershed were cleared for development, fecal coliform levels could increase by over 250%. Consequently, land preservation is an extremely important component of source water protection.

Stormwater Runoff

You may notice that rivers turn brown after heavy rains. That’s because rain runoff scours dirt and sediment from river banks and washes pollutants form the land into the water. Bacteria levels are highest in Philadelphia’s rivers after rain events. According to Rivercast (, conditions on the Schuylkill River are unsuitable for certain types of recreation over 30% of the time due to high bacteria levels.


Agriculture Runoff

According to a federal report, runoff from agriculture land is now considered the primary source of pollutants in streams and rivers in the United States. Over 25% of the land that influences the Schuylkill and Delaware rivers is used for farming. The runoff from land associated with agricultural activities contains bacteria, pathogens, sediment and fertilizers, all of which enter our waterways as runoff during storm events.

Spills and Accidents

Rivers, which serve as drinking water sources not just in Philadelphia, but across the nation, are vulnerable to accidental, natural and deliberate contamination events. Since May 2008, over 50 events including sewage leaks, oil spills and fish die-offs were reported in waterways near Philadelphia. These contamination threats create the need for comprehensive early warning systems for many organizations, purveyors, and industries that rely on high water quality water resources from the Delaware and Schuylkill rivers.

Treated Wastewater Effluent

Hundreds of wastewater treatment plants discharge into the Schuylkill and Delaware rivers above Philadelphia. The Schuylkill River is sometimes as much as 60% treated wastewater discharge during prolonged periods without rain. The water department is closely studying impacts of such high percentages of effluent on overall water quality.

Improper Disposal of Trash/Waste

Many of Philadelphia’s storm drains lead directly to our rivers. Throwing pet waste, leftover paint, toxins or trash down storm drains pollutes our drinking water sources. Through an increased awareness of the connection between “street to stream”, this source of pollution has the potential to be significantly reduced.


Pharmaceuticals get into drinking water because people now take more medications than ever, both prescription and over the counter, and only a small portion of these substances is absorbed in the body. The rest passes through the body, eventually making its way into the rivers and streams that serve as our nation’s drinking water sources. These compounds are at such low concentrations that they cannot be detected unless the most advanced methods are used, and there is currently no indication that such small concentrations pose any public health risk. Studies do show impacts to fish, however, which have constant exposure to these substances.

Pollution from Geese and Wildlife

Geese and other wildlife are sources of contamination in our waterways. A single goose can produce up to three pounds of manure every day and 1,095 pounds of fecal material every year. Just two geese can produce over one ton of fecal material. This waste, which contains bacteria and other harmful pathogens, comes into contact with or is washed into our waterways, presenting public health and drinking water treatment concerns.