DEP cites Pittsburgh Water and Sewer Authority for unapproved water treatment change

PITTSBURGH — The Department of Environmental Protection issued an administrative order Monday, citing the Pittsburgh Water and Sewer Authority for making a substantial modification to its drinking water treatment system without prior approval by the DEP.

Reading this in our app? Tap + above the headline to subscribe to alerts for on this story.

The change, which the DEP said occurred in April 2014, involved the use of caustic soda in place of soda ash to control corrosion in PWSA's water distribution system. PWSA went back to the use of soda ash in January 2016.%



"Preliminary data shows no imminent threat to the public as a result of this unauthorized change. We are asking PWSA to analyze all data from April 2014 to January 2016, the period the authority used caustic soda, and the rest of 2016," DEP Secretary John Quigley said in a written press release. "We have put PWSA on notice that its unilateral decision to change treatment was a clear violation of safe drinking water regulations. PWSA had no authority to modify its treatment without first demonstrating to DEP that the proposed change would not adversely impact the corrosion control treatment, and obtaining DEP approval via a permit amendment."

DEP sampled PWSA water last Friday, as it left the plant on its way into the distribution system. The results showed lead levels at less than one part per billion, and copper levels less than four parts per billion, the DEP said in the press release. The federal Lead and Copper Rule establishes an action level of 15 parts per billion for lead, and 1,300 parts per billion for copper.

PWSA's public water supply permit, approved in 1995, requires the use of soda ash for corrosion control, according to the DEP’s press release. Soda ash, or sodium carbonate, is used because of its ability to prevent corrosion in water pipes, and because it helps to prevent leaching of lead and copper into the water. The DEP said caustic soda, or sodium hydroxide, raises the pH of water to bind up metals, but does not have carbonate to coat water lines and relies on the natural carbonates in the authority's source water from the Allegheny River.

Although caustic soda is approved for use by some water systems, it will only be approved by DEP after proof of its effectiveness in each system

In its administrative order, the DEP is requiring the following of PWSA:

  • Provide initial notice to all 300,000 customers about its prior change in corrosion control chemicals and the measures it is undertaking to evaluate impacts.
  • Complete two rounds of lead and copper tap monitoring from 100 Tier 1 sites throughout the authority's distribution area - with the first set of tests to be completed by June 30, with results to DEP by July 10 - and the second set by Dec. 31, with results to DEP by Jan. 10, 2017.
  • Provide any sampling data PWSA collected since June 1, 2013.
  • Develop a plan to investigate lead levels within its system, the effect of changes to treatment methods for corrosion control and recommendations for appropriate changes to assure the best possible corrosion control measures for the system.
  • Outline in subsequent customer notices details of water sampling and analysis, and updates on investigation of treatment change impacts.

"DEP does not take this action lightly," Quigley said in the press release. "We do not tolerate deviation from water quality regulations that might, in any way, potentially compromise the public's health and safety.”

Earlier this year, the PWSA renewed its efforts to get customers to take advantage of free in-home tap water sampling. Customers who have concerns about their tap water can contact PWSA for free test kits and instructions on how to use them. Information on in-home testing is available on the


The DEP said in the release that the PWSA has cooperated with its initial investigation into the water treatment changes. The DEP expects that the PWSA will continue to comply by conducting the required increased sampling, investigating any adverse impacts from the treatment change and providing outreach to its customers.

The PWSA issued its own statement in response to the DEP’s administrative order that read, in part:

“The order is based on treatment practices during parts of 2014 and 2015 directed by prior management. They are no longer used by PWSA. During that time PWSA switched corrosion control agents from soda ash to caustic soda, both recognized as effective in corrosion control. PWSA failed to follow the proper DEP notification procedure in implementing this change.
“Issuance of this order follows over a month of cooperative discussions between PWSA and DEP. PWSA has already addressed some of DEP's requirements, while others are in the planning stages.”

Pittsburgh Mayor Bill Peduto also issued a statement regarding the DEP’s administrative order that read:

"We take the safety and health of our citizens seriously and have been working in collaboration with DEP and PWSA to make sure that our water continues to be among the highest quality and safety.
“This order is being issued related to a procedural violation that was made by PWSA's former management firm, Veolia Inc. It has been reported to us that Veolia Inc. did not inform DEP of a change in corrosion control methods in 2014. In addition, the board of PWSA was not notified of the change, neither was the City of Pittsburgh.
“We have since removed Veolia Inc. from its management of PWSA, related to other issues. PWSA has also changed its corrosion control methods back to those that were originally permitted by DEP. 
“We will also make sure that any future changes to water treatment are not only appropriately vetted by DEP, but that the public is kept fully informed."
Comments on this article