As stewards of a vital natural and public resource, PWSA is committed to providing safe and reliable drinking water to the approximately 500,000 consumers we serve. That’s why we’re proud to release our 2022 Water Quality Report, which shows a clean bill of health for the quality and safety of your drinking water. Our drinking water customers can have confidence that the water you rely on meets or exceeds all regulatory requirements.
We encourage you to read that full report, found on our Water Quality & Treatment webpage, to learn more about our treatment process and the effectiveness of water quality testing. Because water treatment and quality is a technical topic, we wanted to condense and summarize some of the important techniques our talented teams use to ensure the water coming to your tap is safe and reliable.
Measuring pH. pH is essentially a measure of how acidic or basic a water-based solution is. Looking at a pH scale, a pH of 7 is neutral, a pH above 7 is basic, and a pH below 7 is acidic. Too much acidity is harmful to consumers and can cause corrosion in our pipes.
The pH of our raw water source, the Allegheny River, is consistently between 7 and 8. When that water is first pumped into our plant, we add ferric chloride – a coagulant – causing the pH to drop. This drop is a critical part of the process, better enabling particles to coagulate and settle out of the water.
After additional treatment steps, the water is adjusted through the addition of soda ash until a pH of 7.4 to 8.0 is reached.
Building Orthophosphate Scale. Orthophosphate is a food-grade additive PWSA began using in 2019 to reduce lead in homes that have lead service lines or plumbing. It forms a protective barrier – or “scale” – in the interior of a pipe and prevents it from corroding and leeching lead into tap water.
Orthophosphate is approved by the Environmental Protection Agency (EPA) and successfully used in water systems all across the country.
Controlling for Turbidity. Turbidity is most simply described as water cloudiness. The cloudier the water, the higher potential there is for possible microbial breakthrough, so turbidity is measured continuously throughout the treatment process and distribution system.
Many treatment adjustments are made by our teams throughout the year to keep turbidity as low as possible. The turbidity of the Allegheny River can soar following heavy rainfall, which can stir up sediment and move land-bound pollutants to our waterways. Here we can again use ferric chloride, the coagulant, causing the suspended solids in the raw water to clump together, lowering turbidity. After a few more treatment steps, the water moves to our sedimentation ponds to allow for extra particles to settle out, and is then brought back to the treatment plant where it receives additional disinfection – for instance, it’s put in contact with chlorine at the Clearwell – before it’s put into the distribution system.