PWD provides integrated potable water, wastewater, and stormwater services for Philadelphia and some communities in Bucks, Delaware and Montgomery counties.

[4] The primary mission of the department is the planning, operation and maintenance of both the physical infrastructure and the organized personnel needed to provide high quality drinking water, and to provide an adequate and reliable water supply for all domestic, commercial, and industrial requirements, and to manage wastewater and stormwater to protect and improve the quality of the region's watersheds, especially the Delaware River and the Schuylkill River.

[5] It faces many challenges in meeting the goal of providing safe drinking water, including agricultural, mining, and drilling runoff, chemicals and fuel spilled on streets, radionuclides, and the treated wastewater from the region's inhabitants.

Combined sewers, carrying stormwater and sewage in the same pipe, emptied directly into the city's rivers and streams, and dumping of industrial wastes also went largely unchecked.

In specific, it is made up of the following municipalities: Easttown, Tredyffrin, Aldan, Clifton Heights, Collingdale, Colwyn, Darby, East Lansdowne, Folcroft, Glenolden, Haverford, Lansdowne, Marple, Millbourne, Morton, Newtown, Norwood, Prospect Park, Radnor, Ridley Park, Ridley, Rutledge, Sharon Hill, Springfield, Tinicum, Upper Darby, Yeadon, Lower Merion, and Narberth.

Its reach includes parts of Philadelphia and Montgomery counties, as well as five municipalities: Abington, Cheltenham, Jenkintown, Rockledge, and Springfield.

In 1923, the Northeast Sewage Treatment Plant[25] opened along the Delaware River, but implementation of the rest of the comprehensive system was delayed by the onset of the Depression and World War II.

[25] Philadelphia has three drinking water treatment plants — Samuel S. Baxter on the Delaware River and Queen Lane and Belmont on the Schuylkill.

Before untreated water reaches the city limits, it has traveled as much as 330 miles past farms, factories, businesses and residential areas, each of which contributes its own pollutants to the rivers.

Philadelphia lists climate change, forest clearing and development, stormwater runoff, agricultural runoff, spills and accidents, treated wastewater effluent, pharmaceuticals, pollution from geese and wildlife, and improper disposal of waste and trash as the program's primary concerns related to maintaining high quality drinking water.

[32][33][34][35][36] The Early Warning System was created in order to integrate real time water quality monitoring with the use of river gauges and water quality sensors that analyze and provide data to craft models that can project the downstream spread and estimated arrival of pollution caused by spills, accidents, and floods.

[37] This system assists experts in planning responses to pollution and sends notifications via telephone and email to alert safety officials when these spills have occurred.

This provides an enhanced analysis of tidal flow influences on pollution spills in the Delaware Valley, improving response planning.

[37][43] RainCheck is a program Philadelphia Water employs to help residents capture stormwater and prevent it from causing sewer overflows.

[46] These projects are intended to help Philadelphians contribute to their city- by filtering stormwater runoff that would otherwise end up polluting streams and rivers.

[48][52] The fishway allows shad to migrate up the Schuylkill River to spawn and has led to more than 3,000 fish passing through the ladder, according to a report by the U.S. Army Corps of Engineers.

This grant program is designed for large, commercial properties with lots of impervious surfaces that create stormwater runoff in high volumes, burdening the city's sewer system.

The technology for biogas cogeneration has been endorsed by the U.S. Environmental Protection Agency and allows for electricity and heat to be produced by the methane gas given off during sewage treatment.

[64] The project cost $47.5 million and was financed by Bank of America, the company which technically owns the facility though the city is leasing it for 16 years.

In order to complete the project the city partnered with Ameresco Inc., a company based in Massachusetts that specializes in energy efficiency and infrastructure upgrades for North American facilities.

[65] In this process, sludge digesters at the plant fuel the decomposition of organic materials to produce biogas by removing water vapor, hydrogen sulfide, and siloxane gas.

Green City, Clean Waters confronts a number of challenges Philadelphia faces with aging infrastructure and the impact of climate change on human health[66][67] but the program's driving factor is the reduction of combined sewer overflows (CSOs).

[68] The following year on March 31, 2015, Green City, Clean Waters won the APA National Planning Excellence Award for Implementation.

[73][74] More than a hundred years ago, Philadelphia built its sewers so that sewage, stormwater runoff, and gray water would all flow underground into the same pipe.

Philadelphia Water aims to protect the watershed with Green Stormwater Infrastructure and create a more environmentally friendly city.

A Philadelphia-based company called NovaThermal Energy partnered with Philadelphia Water on a project that warms a building with heat derived from sewage.

Using low-cost technologies such as the Arduino microcontroller and the Raspberry Pi, greenSTEM allows students to monitor schoolyard gardens using web-connected sensors.

[77] In 2014, greenSTEM worked with students to design innovative soil-moisture monitoring systems for their school gardens called Root Kits.

In addition to monitoring soil-moisture data, the birdhouses contain an infrared camera that captures live footage of the birds nesting inside.

Students from Science Leadership Academy's Beeber campus have engaged in programming Root Kits for other schools and built birdhouses to hold the soil-moisture sensors and cameras.