Water Quality & Treatment

A scene from the Water Treatment Plant in Aspinwall overlooking the Allegheny River, the source of Pittsburgh's drinking water Pittsburgh's Allegheny River is the source of our drinking water. The treatment process begins at the Water Treatment Plant in Aspinwall.

The Pittsburgh Water and Sewer Authority provides service to more than 300,000 customers throughout the City of Pittsburgh and surrounding areas. We are the largest combined water and sewer authority in Pennsylvania producing an average of 70 million gallons of water daily and providing drinking water to the majority of Pittsburgh.

Ensuring the safe and reliable delivery of drinking water is our top priority. Our dedicated staff at the water treatment plant and in our lab are constantly monitoring and measuring the quality of our drinking water to ensure that it meets all state and federal drinking water requirements. 

A closer look at our treatment process and water quality

Annual Drinking Water Quality Reports

A woman working in the lab at the Water Treatment Plant in Aspinwall

Each year we produce an Annual Drinking Water Quality Report that outlines our treatment process and the contaminants that may be found in our source drinking water prior to treatment. We monitor and test the level of these contaminants before, during, and after the treatment process to maximize their reduction and removal. 

We regularly test for approximately 100 different chemical and microbial constituents. This includes microbial contaminants, inorganic contaminants, pesticides and herbicides, organic chemical contaminants, and radioactive contaminants - all of which are regulated by the Environmental Protection Agency and Pennsylvania Department of Environmental Protection. 

Use the links below to review our most current and past Annual Drinking Water Quality Reports.

2018 Annual Drinking Water Quality Report

2017 Annual Drinking Water Quality Report

2016 Annual Drinking Water Quality Report

2015 Annual Drinking Water Quality Report

2014 Annual Drinking Water Quality Report

2013 Annual Drinking Water Quality Report

2012 Annual Drinking Water Quality Report

2011 Annual Drinking Water Quality Report

2010 Annual Drinking Water Quality Report

2009 Annual Drinking Water Quality Report

2008 Annual Drinking Water Quality Report

2007 Annual Drinking Water Quality Report

2006 Annual Drinking Water Quality Report

2005 Annual Drinking Water Quality Report

2004 Annual Drinking Water Quality Report

2003 Annual Drinking Water Quality Report

2002 Annual Drinking Water Quality Report

2001 Annual Drinking Water Quality Report

Water Treatment Process

Infographic illustrating PWSA's water treatment process

The Allegheny River is the source of our drinking water. Once we draw water from the river, it processes through the Water Treatment Plant before arriving at your tap as drinking water. We produce approximately 65 - 75 million gallons of water every day, and it can take up to three days for the water to complete the treatment process.

Once treatment is finished, the water enters the distribution system. Through a complex network, water is pumped to reservoirs and tanks that store treated drinking water. As it leaves these storage facilities, gravity creates pressure to push water through miles of pipes to your home or business.    

Steps of the water treatment process

Coagulation: (Ferric Chloride, Potassium Permanganate, Carbon, Catatonic Polymer) These chemicals produce a reaction that allows the particles from the river to stick together, making them easier to remove.

Sedimentation: During this step, additional time is provided for particles to form and settle out of the water.

Filtration: A filter consisting of anthracite coal and sand allow water to pass through at a slow rate to remove any remaining particles.

Disinfection: (Sodium Hypochlorite) This chemical is added after filtration in a storage tank, known as the Clearwell, to ensure that the disinfectant has enough contact with the water to remove microbial particles.  

Corrosion ControlIn April of 2019, we began using orthophosphate to reduce lead levels in tap water. A year-long study found orthophosphate to be more effective at reducing corrosion than our previous treatment method using soda ash and lime. For more information about the use of orthophosphate in our drinking water, please visit www.lead.pgh2o.com.

Fluoride: (Hydrofluosilicic Acid) We add fluoride to our drinking water at the level recommended by the Center for Disease Control and Prevention.

Tour Our Water Treatment Plant

Detention basins inside the water treatment plant

We are happy to host your group on a tour of the Water Treatment Plant. It's a fascinating experience to learn about your drinking water. Check out the Tour Our Water Treatment Plant page to schedule one.

Orthophosphate

Graphic comparing a pipe with a protective layer of orthophosphate to one without.

In April of 2019, we began using orthophosphate to reduce lead levels in tap water.

Orthophosphate is a food-grade additive that forms a protective layer inside of lead service lines, creating a barrier between the lead pipes and the water flowing through them. It is approved by the Environmental Protection Agency (EPA) and used in water systems across the world, including sections of the City of Pittsburgh served by Pennsylvania American Water Company.

A year-long study found orthophosphate to be more effective at reducing corrosion than our previous treatment method using soda ash and lime. The Pennsylvania Department of Environmental Protection (PA DEP) agreed with the study’s findings and approved corrosion control upgrade to orthophosphate.

We built four new facilities to add orthophosphate to the water distribution system after it leaves the Water Treatment Plant. The longer orthophosphate is present in the drinking water system; it becomes more effective at reducing lead levels. Early testing results indicate that our addition of orthophosphate is an effective method to reduce lead levels. 

For more information about the use of orthophosphate in our drinking water, please visit www.lead.pgh2o.com.

Lead Test Results

We conduct compliance testing for lead using the methodology prescribed by the Pennsylvania Department of Environmental Protection and Environmental Protection Agency guidelines. Samples are collected from worst-case scenario homes that were verified to have lead service lines or plumbing. Please visit lead.pgh2o.com to review lead test results dating back to 2004. 

Per- and Polyfluoroalkyl Substances (PFAS)

Infographic illustrating how PFAS cycles through the environment

To stay ahead of potential risks and future regulatory requirements, we are currently monitoring per- and polyfluoroalkyl substances (PFAS). They are an unregulated contaminant that the Environmental Protection Agency notes may present a cancer risk. Recent testing has not shown quantifiable levels of PFAS.

Test Results

Use the links below to review our most current and past test results for per- and polyfluoroalkyl substances. 

August 2019

February 2019

August 2018