Our sewer system includes 1,200 miles of sewer lines and more than 25,000 storm drains.
Historic image of Pittsburgh Water sewer being constructed
Our first sewer lines were built as early as 1840 in present-day Shadyside and Oakland. By 1908, more than 390 miles of underground sewer lines were in place, establishing the start of our combined sewer system that is still used today.
We send wastewater – the water you flush down your toilet or water that goes down your drain 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.
While sewers serve a simple purpose – to move sewage and stormwater away from homes and businesses – a sewer failure can be very impactful.When sewer walls crack or collapse, they can cause sinkholes, sewer backups, and sewage service impacts to our customers. Additionally, full sewer replacements can be a costly and time-consuming project.
This is why Pittsburgh Water is focusing a majority of its approximately $182 million capital plan over the next four years on proactive sewer work. This involves sewer rehab, which repairs small cracks and debris without a trench, and sewer relocation from risky locations like under railroad tracks or on steep hillsides.
Learn More about Types of Sewer Construction Projects
Sewer Lining and Rehabilitation Projects
We will use extensive televised footage collected of our sewer to determine which portions of sewer can be proactively rehabbed before they fail. This work is done without a trench, using sewer lining technology. Sewer liners are a sleeve that is cured to the inside of the pipe, creating a protective barrier that secures cracks in the pipe and prevents leaks.
Learn more about Sewer Lining
Sewer Under Structures
Sewers that have been built underneath structures - which includes buildings, bridges, or railroads – can be an even bigger risk when they fail due to their location. For this reason, we have committed to identifying those locations and creating a new pipe design that is located in public space or in a safer place. Pittsburgh Water’s engineering team will work with land owners to make necessary adjustments and avoid costly and disruptive sewer failures in the future.
Sewer Reconstruction
We must be ready to respond to emergency sewer situations that cause flooding, basement back-ups, and other quality of life issues that impact customers.
Large Diameter Sewer Rehabilitation
Our largest sewers in the system, which are responsible for carrying large volumes of sewage and stormwater, require special attention. For the next four years, we will address these sewers 36-inches and above, restoring structural integrity, removing roots, and repairing cracks that may cause infiltration into the pipe. Through this work, we will also collecting important televised footage of our largest sewer mains.
Manhole, Catch Basin, and Inlet Repair and Replacement
Pittsburgh Water maintains thousands of access points and drainage structures throughout the city to keep water and sewer systems functioning properly. These components are critical for managing stormwater, preventing flooding, and allowing crews to access underground infrastructure for maintenance. Here’s what each one does and why repairs are necessary:
Manholes
Purpose: Manholes provide access to underground sewer and water lines for inspection, cleaning, and repairs.
Why Repairs Are Needed: Over time, manhole frames and covers can deteriorate, shift, or become damaged due to traffic, weather, or age. This can lead to leaks, infiltration, or unsafe conditions.
Repair Process: Crews remove the old frame and cover, adjust the structure to proper grade, and install a new frame and lid. In some cases, the manhole interior is relined to prevent leaks.
Catch Basins
Purpose: Catch basins collect stormwater runoff from streets and direct it into the sewer system, preventing flooding and roadway damage.
Why Repairs Are Needed: Heavy traffic, freeze-thaw cycles, and debris buildup can damage the basin or cause blockages.
Repair Process: Crews clean out debris, rebuild the basin walls if needed, and reset the grate to ensure proper drainage.
Inlets
Purpose: Inlets are openings along curbs or streets that allow water to flow into the storm sewer system.
Why Repairs Are Needed: Inlets can crack, collapse, or become clogged, reducing their ability to manage stormwater.
Repair Process: Crews excavate around the inlet, replace damaged components, and restore the surrounding pavement or curb.
Why It Matters: These repairs help prevent street flooding, protect water quality by reducing pollutants entering rivers, and maintain safe access for crews to service underground infrastructure. They’re part of Pittsburgh Water’s ongoing commitment to modernizing and maintaining the city’s water and sewer systems.
Urgent Repairs
An Urgent Sewer Repair Contract is a specialized agreement Pittsburgh Water maintains with contractors to address emergency sewer issues that require immediate attention. These repairs are outside of routine maintenance and cannot wait for standard scheduling because they pose risks to public health, safety, or property.
How Does the Sewer System Work?
In Pittsburgh, approximately 75 percent of the sewer system is a combined system, meaning that stormwater and wastewater flow through the same pipe. The remaining 25 percent is a separated system, which means that wastewater flows through one sewer pipe and stormwater flows through another.
This network is essential for protecting public health and the environment, but because much of it is over 100 years old, Pittsburgh Water is investing heavily in upgrades to keep the system safe and reliable for generations to come.
How the System is Designed
- Private Laterals: Each individual property connects to the system through what are known as private laterals, which are the smaller pipes running from your home or building to the public lateral under the street.
- Public Laterals: Maintained by Pittsburgh Water, these laterals are the portion of the sewer line that runs under the public right-of-way (usually the street) and connects to the larger sewer main. They typically serve as the transition point between private laterals owned by the property owner and the public sewer system, maintained by Pittsburgh Water.
- Sewer Mains: Maintained by Pittsburgh Water, sewer mains collect wastewater from multiple laterals, carrying it through the local neighborhood towards trunk lines.
- Trunk Lines: Maintained by Pittsburgh Water, sewer trunk lines are much larger than typical sewer mains because they carry wastewater across entire neighborhoods. In Pittsburgh, trunk lines can be 3 feet (36 inches) in diameter or even larger!
- City-sized Interceptors: Eventually, all of this wastewater flows into massive interceptor pipes. The interceptors are not managed by Pittsburgh Water, instead they are managed by ALCOSAN (Allegheny County Sanitary Authority). ALCOSAN treats the water before releasing it back into our rivers.
ALCOSAN, 3 Three Rivers Wet Weather, and CivicMapper created the Flush It! tool. The tool shows the path wastewater takes to the ALCOSAN treatment facility from any address within their service area. Enter your address to follow your flush to ALCOSAN.
How To Handle A Sewer Backup
It's never pleasant, but on occasion basements and sewers back up into homes and business throughout Pittsburgh. When this happens, you'll want to know what to do and who to call. Take the time to prepare by reading these helpful steps for handling a sewer backup.
Defend Your Drains
Fats, oils, and grease (FOG), wipes, trash, medicine, paint, and many other items should never be flushed down your toilet or poured down your drain because they can cause blockages, flooding, sewage back-ups, and health hazards. Learn how to protect your pipes and the public sewer system on our Defend Your Drains page.