Expert Report

Each report is produced by a committee of experts selected by the Academy to address a particular statement of task and is subject to a rigorous, independent peer review; while the reports represent views of the committee, they also are endorsed by the Academy. Learn more on our expert consensus reports.

The city of Pittsburgh and surrounding area of southwestern Pennsylvania face complex water quality problems, due in large part to aging wastewater infrastructures that cannot handle sewer overflows and stormwater runoff, especially during wet weather. Other problems such as acid mine drainage are a legacy of the region's past coal mining, heavy industry, and manufacturing economy. Currently, water planning and management in southwestern Pennsylvania is highly fragmented; federal and state governments, 11 counties, hundreds of municipalities, and other entities all play roles, but with little coordination or cooperation. The report finds that a comprehensive, watershed-based approach is needed to effectively meet water quality standards throughout the region in the most cost-effective manner. The report outlines both technical and institutional alternatives to consider in the development and implementation of such an approach.

Key Messages

  • Almost all of the water quality data available to the committee were derived from single studies in specific areas for limited durations. As a result, it is difficult to say how extensive and significant the water quality contamination is.
  • Despite high levels of pathogens and indicators in regional waters, there is no evidence that southwestern Pennsylvania has recently experienced any waterborne disease that would link impaired source water quality with human health effects.
  • From a regulatory perspective, the most important water quality problem in the region in terms of the potential for adverse human health effects is controlling microbial contamination of streams that derives from the effect of wet weather conditions on sewer systems (CSOs, SSOs, and stormwater), failing septic systems, and agricultural and urban runoff.
  • Groundwater used for public drinking supplies generally meets water quality guidelines, private wells show significant variability, and the effects of mining are apparent.
  • Microbiological water quality in many tributaries does not meet standards in either wet or dry weather, suggesting the potential for multiple sources of pollution. Pathogenic protozoa and indicator organisms are routinely detected in surface waters used as drinking water sources in the region.
  • One or more regional decision-making authorities should take responsibility for leading the development of a Comprehensive Watershed Assessment and Response Plan that would have as its principal objective the meeting of water quality standards throughout the region in the most cost-effective manner
  • Surface waters in southwestern Pennsylvania are impaired for a variety of uses including recreational use due to microbiological indicators and pathogens in surface water, fish consumption due to organic (PCBs) and inorganic (Hg) contamination, and aquatic life use due to metal concentrations and low pH.
  • The first route to successful improvement of water quality in the region is to optimize utilization of existing infrastructure.
  • The major causes of water quality impairment in the Commonwealth of Pennsylvania are the following: (1) acid mine drainage, (2) agriculture, (3) urban and stormwater runoff, and (4) human waste handling.
  • The region needs a coordinated, well-funded program for oversight and routine maintenance of cluster and individual septic systems. Such a program can be self-sustaining through user charges providing they are applied on a cooperative regional or county basis.
  • There are no comprehensive estimates of the economic benefits of addressing the remaining water quality problems for southwestern Pennsylvania or from proposed projects to address the region's water quality problems.
  • Water in the three main rivers in southwestern Pennsylvania generally shows adequate dissolved oxygen, is at near-neutral pH, and does not exceed water quality standards for inorganic constituents. Pesticides and volatile organic compounds were detected at levels below maximum contaminant levels in waters in southwestern Pennsylvania.
  • Water planning issues in southwestern Pennsylvania need to be addressed on a regional and holistic basis, taking into account water quality; water supply; flood hazard mitigation; aquatic and riparian habitat protection and restoration; and recreation.
  • Water quality problems in southwestern Pennsylvania are complex and region wide.