Our Source Water
The Allegheny River is the source for PWSA's drinking water. The headwaters of the Allegheny is located 352 miles northeast of Pittsburgh. 

PWSA's Commitment to Our Source
At PWSA, we are doing our part to conserve and improve the condition of our waterways which means taking steps to manage stormwater and reduce pollution entering our streams and rivers. PWSA’s green infrastructure projects slow the flow of stormwater over land and actions such as separating stormwater flows from pipes which carry sewage significantly improves water quality. We continually monitor the conditions of the Allegheny and collaborate with our community and regulatory partners to protect the integrity of this vital resource. 

The History of the Allegheny

The Allegheny that we know today was largely shaped by the surreal, land-changing forces during the ice ages over 12,000 years ago. Before the most recent ice age, the Allegheny River was comprised of three “little Alleghenies”, all of which used to flow north towards Canada (Picture A). During the ice age, an ice sheet reached as far south as modern day Moraine State Park, south of Erie (Picture B). These little Alleghenies were transformed at the end of the ice age and reshaped into a single river as massive amounts of meltwater from receding glaciers overwhelmed the original waterways. This carved a new path and reversed the flow of the river to a southerly direction (Picture C). 


 
Ecology of the Allegheny

The Allegheny’s riverbed is sandier than the Monongahela and Ohio Rivers which has led many Pittsburghers to recall it as the clearest of our three rivers. This relative clarity hearkens back to its distant ice-age past; the river carries glacial stones and sands southward contributing to the formation of the river’s many islands and supporting the most populous freshwater mussel habitat in the world in its upper stretches. 

The Upper Allegheny winds through national forest, pastoral farmland, small towns, and valleys. The scenic nature, remarkable fish and wildlife varieties, and recreational opportunities preserve this upper portion under the 1968 Wild and Scenic Rivers Act. Recognition under this act is a distinction earned by only a tiny percentage of American Rivers. As the Allegheny flows downstream to Pittsburgh, its waters and surrounding environment are protected to benefit current and future generations.  
 

The condition of the upper Allegheny benefits those downstream who receive its waters and is a reminder that clean waterways are the result of collective care and concern. Each individual’s decisions on land affect water and are amplified along the course of the entire river. 

Links:
National Wild and Scenic Rivers System
PA Wilds Allegheny River Recreation
National Weather Service Real Time River Monitoring
USGS Water Quality Portal

Where We Provide Service: 
To learn where we provide drinking water services, view our Service Area Map. 
If your place of residence falls outside of our service area and you are not sure who your provider is, check out the PA DEP's Public Water Systems page. You can type in an address and easily find the water provider for that region. 
 

How Is the Water Treated? 
At the Pittsburgh Water and Sewer Authority (PWSA), we take immense pride in delivering clean and safe drinking water to our communities served. We understand the importance of providing transparent information regarding the quality and safety of the water you receive and want to assure you that the water supplied by PWSA meets or surpasses all federal and state regulations for drinking water quality. Our commitment to maintaining the highest standards of water safety is unwavering, and we employ rigorous monitoring and testing procedures to ensure the continued delivery of clean and safe water.

• The Water Treatment Process starts with the Allegheny River. On average, 65–75 million gallons of water from the Allegheny River enter through intake pipes and are lifted to the Screen Room, then moving through a series of screens which filter out leaves and debris.
• Water travels to the Clarifier Building where compounds are added and mixed into the water, causing fine particles like clays and silts to settle out.
• The water is sent to large basins for storage and given additional time to settle. After some time, the water exits and continues to filtration.
• In the Filter Building, water moves through 18 gravity filters filled with carbon and sand to further remove impurities. Chlorine is added to begin disinfection.
• Water enters the 40 million gallon Clearwell to finish disinfection. Additional compounds are added to treat the water and protect pipes from corrosion.
• The water exits the Clearwell and will now enter The Water Distribution System which is comprised of a series of pipes and holding tanks distributing the water to our customers.

When water flows from your tap or goes down your drain, you don’t necessarily think about it. But there’s a lot of science, engineering, maintenance, and thought to make sure water is managed properly.  Explore the links below to learn about the stormwater system, watershed and discover how you can help manage stormwater runoff.

How the Stormwater System Works
Our sewer system includes 1,200 miles of sewer lines and more than 25,000 storm drains. When it rains, stormwater enters inlets along our roadways and other surfaces, and the storm sewer pipes send the stormwater directly to our streams and rivers. 

Approximately 75 percent of the sewer system is a Combined System, meaning that stormwater and wastewater (the water you flush down your toilet or water that goes down your drain) flow through the same pipe.

The remaining 25 percent is a Municipal Separate Storm Sewer System (MS4), which means that wastewater flows through one sewer pipe and stormwater flows through another.  

We send wastewater to ALCOSAN, the regional wastewater treatment plant along the Ohio River. They treat wastewater for the 83 municipalities in Allegheny County, including the City of Pittsburgh.

Visualize Your Watershed
All precipitation that falls eventually makes its way into a waterway and everything that we do on land eventually affects the water. With this interactive map tool, you can visualize where the many smaller watersheds within Allegheny County. type in your address to discover which waterway receives runoff from your property.
For a more zoomed out look at our watersheds at the state-level, check out PA's Watershed Regions map. 
 

Reducing Pollution To Our Waterways
When it storms, stormwater picks up litter, oil, road salt, and other pollutants on the ground before flowing through storm drains to our streams and rivers. This pollution harms local water quality, fish and wildlife, and recreation.

There is a lot you can do to help reduce pollution from entering our waterways with simple, everyday actions. Visit our Help Manage Stormwater page to discover tips!


Stormwater Resource Links

Southwestern Pennsylvania's Homeowner's Guide to Stormwater: A thorough guide to actions you can take around your home to make a difference in managing stormwater on your property.
Preventing Stormwater Pollution in Our Municipal Operations: A guide for preventing pollution at the municipal level. 

Partners In Cleaner Waterways and Volunteer Opportunities

Allegheny Cleanways: Volunteer opportunities throughout the region including riverfront cleanups and storm grate cleanouts.

Upstream Pittsburgh: Volunteer opportunities including stream sweeps, greenspace workdays and resources for rain barrels. 

Penn State Master Watershed Steward Program: Volunteer training on a variety of water resource topics, including groundwater, stream ecology, wetlands, invasive plants, water recreation and stormwater management.

A 1916 Parade celebrates the steep decline in typhoid in Pittsburgh.

Before Water Treatment...

Pittsburgh, the city which once produced over half of the nation’s steel, simply would not be if not for the waterways which directly led to the establishment, growth and development of the industries that placed it on the map.  For this reason, at the Pittsburgh Water and Sewer Authority (PWSA), our gratitude for our waterways runs deep. As we peer back at the service our rivers have provided to our steel city, we are reminded of their inherent value. 
 

Since the early 1800s, our three rivers have served as an indispensable transport route. With an abundance of coal, iron and timber nearby, Pittsburgh rose to prominence as a steel town with goods coming in by waterways. Water was so important as a transport option that Pittsburghers lobbied in the 1840s to have canals and aqueducts built throughout the city to make the delivery of raw materials by water even easier.  

Raw Sewage Flows from a pipe into Saw Mill Run

The city’s population increased four-fold during the decades of the canal system’s operation, but with a growing population and more industry came less care for our rivers. By the 1880s, hundreds of boats were navigating Pittsburgh’s rivers, waste from factories was being dumped into the water and it was customary for sewage to be sent directly into the river. The terrible result was that Pittsburgh had the highest typhoid fever mortality rate of any city in the nation by the early 1900s.  Pittsburgh was highly affected by its poor water conditions, and this is directly linked to lack of water treatment services. 

The dismal state of Pittsburgh’s rivers and drinking water would begin to improve as new regulations were set in place and commitments to better public health outcomes became a priority. After seeing the success of filtration plants in other cities, Pittsburgh erected a demonstration filter in 1895 which proved that slow sand filtration was the most economical and effective means at the time to purify the water. 

Construction in progress on the slow sand filtration plant, 1907

Construction of Pittsburgh’s first filtration plant began in 1905 on the northern bank of the Allegheny River on the site of the present-day Waterworks Plaza. The first filtered water was delivered to the city in 1907. All of downtown and the east end was receiving filtered water by the spring of 1908 and South Side by February of 1909. By 1912, rates of Pittsburghers succumbing to typhoid fever would drop by over 900 percent.

Further Reading and links:

The Search for Pure Water in Pittsburgh: The Urban Response to Water Pollution, 1893-1914: Western Pennsylvania History: 1893-1914 | Western Pennsylvania History: 1918 - 2020, journals.psu.edu/wph/article/view/3450/3281. 

Blackley, Katie. WESA. Aqueducts, inclines and mules: How the Pennsylvania Canal changed the Commonwealth. Available at: https://www.wesa.fm/development-transportation/2020-04-08/aqueducts-inclines-and-mules-how-the-pennsylvania-canal-changed-the-commonwealth. 

 The Fate of Sewage and Stormwater from Medieval Times in Europe to Today in Pittsburgh

DiscoverWater.org

Turn screen time into learning time with free online water games designed for kids ages 7-12! Explore interactive activities and quizzes about different water topics, and build a personalized "Take Action!" poster at DiscoverWater.org.

Drinking Water Maze

Follow your water as it travels from the river to your home and back to the river again! This printable maze is available in English or Español. 

Test Your WaterSense

Help water-saving hero Flo navigate through a maze of water pipes and answer water-efficiency questions while avoiding Water Waster monsters! Check out the US EPA Test Your WaterSense game and learn more on the US EPA WaterSense for Kids webpage. 

Fix a Leak Puzzle Sheet

Help water-saving hero Flo complete these word puzzles to fix water-wasting leaks around the house! This printable US EPA puzzle sheet is available in English or Español. Learn more on the US EPA WaterSense for Kids webpage. 

The Basics of Freshwater: Crash Course Kids 14.1

We have a lot of water on Earth, but we can't actually drink most of it. This YouTube episode of Crash Course Kids based on 5th-grade science explains the difference between freshwater and saltwater and why freshwater is so important.

Freddy the Fish Teaches About Stormwater

In this YouTube video created by the North Central Texas Council of Governments, Freddy the Fish explains what happens to rain after it hits the ground, where storm drains lead to, and what we can do to help prevent water pollution. 

Learn about the water cycle and good water habits while making art
 

• The Water Cycle Coloring Page in English or Español
• Storm Drain Coloring Page in English or Español
• Saving Water Coloring Page in English or Español
• Fats, Oil, and Grease (FOGs) Coloring Page in English or Español
• Wash Your Hands Coloring Page in English

DiscoverWater.org

Turn screen time into learning time with free online water games designed for kids ages 7-12! Explore interactive activities and quizzes about different water topics, and build a personalized "Take Action!" poster at DiscoverWater.org.

Test Your WaterSense

Help water-saving hero Flo navigate through a maze of water pipes and answer water-efficiency questions while avoiding Water Waster monsters! Check out the US EPA Test Your WaterSense game and learn more on the US EPA WaterSense for Kids webpage. 

Pittsburgh Water Words Crossword Puzzle

Quiz yourself on water words relevant to Pittsburgh! Fill out this crossword puzzle on the Crossword Labs website or download a printable version. Check your answers using the key. 

Take the Stormwater Runoff Challenge

Test your understanding of water facts and pollution with this fun crossword puzzle from the US EPA. The printable crossword puzzle can also be used as a placemat. 

Runoff Simulation

Use this animated model created by Stroud Water Research Center to learn how land use and soil together determine whether rainfall infiltrates into the soil, runs off into streams, or is evaporated and transpired by plants. 

Model My Watershed

Use this web app created by Stroud Water Research Center to analyze real land use and soil data in your neighborhood or watershed, model stormwater runoff and water-quality impacts, and compare different conservation or development scenarios. 

How's My Waterway

Research the condition of your local, state, and national waters using this web app created by the US EPA. Learn about water quality impacts and how you can help protect your local waterways. 

Pollution Awareness: What's Wrong with This Picture?

Scout out the scene and look for places where someone's actions might be harming the environment! Check out this detective game on the US EPA website.

Pittsburgh Water Words Crossword Puzzle

Quiz yourself on water words relevant to Pittsburgh! Fill out this crossword puzzle on the Crossword Labs website or download a printable version. Check your answers using the key. 

Take the Stormwater Runoff Challenge

Test your understanding of water facts and pollution with this fun crossword puzzle from the US EPA. The printable crossword puzzle can also be used as a placemat. 

Runoff Simulation

Use this animated model created by Stroud Water Research Center to learn how land use and soil together determine whether rainfall infiltrates into the soil, runs off into streams, or is evaporated and transpired by plants. 

Model My Watershed

Use this web app created by Stroud Water Research Center to analyze real land use and soil data in your neighborhood or watershed, model stormwater runoff and water-quality impacts, and compare different conservation or development scenarios. 

How's My Waterway

Research the condition of your local, state, and national waters using this web app created by the US EPA. Learn about water quality impacts and how you can help protect your local waterways. 

Pollution Awareness: What's Wrong with This Picture?

Scout out the scene and look for places where someone's actions might be harming the environment! Check out this detective game on the US EPA website.

Check out our YouTube Channel to see what we are doing in the community. We are developing more video content to help highlight many of our projects and programs. Click subscribe to see what's coming next!