Allegheny County Sanitary Authority
| Company type | Municipal authority |
|---|---|
| Industry | Wastewater treatment |
| Founded | 1940s |
| Headquarters | Allegheny County , United States |
Area served | 83 municipalities including Pittsburgh, Pennsylvania |
| Products | Wastewater treatment services |
| Website | www |
Allegheny County Sanitary Authority (ALCOSAN) functions as a municipal entity within Allegheny County, Pennsylvania, delivering wastewater treatment services to 83 municipalities, including the city of Pittsburgh. Its primary sewage processing facility is situated along the Ohio River, downstream from Pittsburgh.
Early water management in Pittsburgh
During Pittsburgh's formative years, the Allegheny and Monongahela rivers were utilized both as sources of drinking water and as conduits for sewage disposal. While affluent citizens often consumed bottled water, a large portion of the population depended on untreated river water. Historically, Pittsburgh recorded the highest typhoid incidence rates nationwide; in the late 1800s, nearly half of immigrant men contracted typhoid within two years after arriving. The introduction of water filtration in 1907 led to a marked decline in typhoid fatalities.
With population expansion, by approximately 1880, combined sewer systems replaced earlier cesspools and privies, channeling wastewater directly into local tributaries and rivers. Despite the Pennsylvania Pure Waters Act of 1905 prohibiting the release of untreated sewage by new infrastructure, Pittsburgh persisted with this practice. Early 20th-century public health advocates called for sewage treatment facilities, but financial constraints delayed progress. By the 1930s, typhoid mortality had fallen to less than one per 100,000 residents. At that time, it was commonly believed that rivers served primarily to transport waste downstream, placing responsibility for water treatment on downstream communities.
Following World War II, heightened sanitation standards and efforts to rehabilitate Pittsburgh’s waterways prompted the Pennsylvania Sanitary Water Board to mandate cessation of raw sewage discharges. In response, Allegheny County established Alcosan during the 1940s to tackle this issue. Funding posed significant challenges due to disagreements between Pittsburgh and neighboring areas; however, these were resolved when Alcosan obtained a $100 million loan in 1955—the largest sewage treatment financing in U.S. history at that time. Operations commenced in 1959, effectively ending routine discharge of untreated sewage into local rivers.
Current operations
By the early 2000s, Pittsburgh’s rivers had experienced substantial improvements in cleanliness compared to previous decades, enabling recreational activities such as fishing and waterskiing. Nevertheless, water quality advancements have not fully met federal regulatory requirements, and Pittsburgh continues to have the highest count of combined sewer outfalls nationwide.
Since 2004, Alcosan has organized an annual open house event aimed at informing the public about forthcoming infrastructure projects. The authority also allocates resources toward lobbying; in 2009 alone, it expended $73,000 with Buchanan, Ingersoll & Rooney and $48,000 with Eckert, Seamans, Cherin & Mellott to advocate before the Pennsylvania General Assembly.
Challenges with sewer overflows in Pittsburgh
Much of Pittsburgh’s sewer and stormwater infrastructure dates back nearly a century and developed unevenly during rapid urban growth around 1900. Alcosan’s jurisdiction includes both separate sewer systems—where wastewater is treated while stormwater is discharged directly into tributaries—and combined sewers that integrate sewage with stormwater runoff. Heavy precipitation frequently causes combined sewers to release untreated sewage into rivers through combined sewer overflow events. Even separated systems occasionally experience sanitary sewer overflows due to leaks or incorrect connections.
In 2004, the EPA estimated annual discharges of roughly 16 billion gallons of raw sewage into waterways serving Pittsburgh. By 2009, unsafe river contact conditions occurred approximately 70 days each year because of these overflow incidents. Smaller tributaries endure even more severe contamination; a 2005 study by Carnegie Mellon University revealed only 32% of Allegheny County streams complied with Pennsylvania’s fecal coliform standards, with some tributaries exceeding acceptable limits by thousands-fold.
After persistent violations of the Clean Water Act, Alcosan entered into a consent decree in 2007 with the EPA and Pennsylvania Department of Environmental Protection requiring development of a comprehensive plan to reduce sewage overflows. This plan was mandated for submission by 2012 and must be fully executed by 2026.
Sewer overflow notifications
Advisories regarding river water quality serve to inform the public about possible contamination, recommending caution during activities like fishing and boating. These alerts do not ban river usage but specifically advise sensitive individuals—such as those with open cuts or compromised immune systems—to limit exposure to the water.
Typically issued from May 15 through September 30, the prime season for river recreation, these warnings correspond with heightened risks from sewer overflow events and stormwater discharge. During active advisories, local marinas hoist orange CSO (Combined Sewer Overflow) flags to notify visitors.
Sewer overflows happen when intense rainfall overwhelms combined sewer systems, causing untreated sewage and stormwater to be released into nearby rivers and streams. Water conditions generally normalize within 24 to 36 hours after rainfall stops.
This advisory system was established in 1995 in response to federal public notification mandates. The number of advisories fluctuates with weather patterns; for instance, the dry summer of 1999 saw eleven advisories lasting a total of 33 days, whereas in 1998 there were ten advisories spanning 50 days.
To complement the CSO flag program, ALCOSAN offers the Sewer Overflow Advisory Key (SOAK), an online tool that displays current water quality using a color-coded scheme:
- Green: Dry weather conditions; exercise caution when using rivers
- Red: Active overflows during wet weather; reduce water contact
- Yellow: Overflows have stopped; water quality may still be compromised
SOAK updates throughout the May to September boating season, with conditions usually improving from yellow back to green within 48 hours after overflow events conclude.
Historical projections of cost increases
In 2007, Alcosan estimated that fulfilling the consent decree requirements would amount to $1 billion. By 2009, however, officials from Allegheny County and Pittsburgh anticipated expenses reaching $21 billion by 2026—significantly surpassing Alcosan’s original figure—and cautioned that this could increase annual household charges by $425 to $3,104 without additional funding sources. Some forecasts even projected costs as high as $50 billion. Residential water rates climbed from $2.98 per 1,000 gallons in 2007 to $3.77 in 2009.
Wet weather strategy
By 2012, the average annual Alcosan bill per household was $262; when combined with municipal fees, total sewage charges averaged approximately $430 per household. On July 31, 2012, Alcosan unveiled a draft Wet Weather Plan aimed at meeting EPA consent decree mandates requiring the elimination of all Sanitary Sewer Overflows (SSOs) and an 85% reduction in Combined Sewer Overflows (CSOs) by 2026.
The Selected Plan exceeded these targets at an estimated cost of $3.6 billion (in 2010 dollars), incorporating 25 miles of new tunnels to eradicate SSOs and capture 96% of CSOs. Despite its effectiveness, Alcosan regarded this option as prohibitively expensive due to potential tripling of customer sewage expenses.
Consequently, Alcosan proposed a Recommended Plan costing $2 billion (2010 dollars), which would reduce SSOs by 90% and CSOs by 79%. Although this falls short of EPA goals, it is more financially feasible—expected to double sewage bills overall with an approximate annual increase of 11%. Alcosan sought EPA approval for modifying the consent decree accordingly; however, EPA historically has resisted adjusting agreements based on affordability concerns within the Mid-Atlantic region.
Environmental advocates criticized components of the plan, including the use of large-diameter pipes for stormwater control. In response, early in 2017 Alcosan initiated a $9 million grant program designed to assist municipalities in implementing green infrastructure projects such as stream restoration aimed at reducing overflows.
Discussions between Alcosan and the EPA regarding revisions to the plan remain ongoing.
Consent decree implementation
In 2009, Alcosan proposed pilot projects in Munhall and Millvale aimed at addressing combined sewer issues within its jurisdiction. Nonetheless, these initiatives were never realized.
See also
External links
- Allegheny County Sanitary Authority
- Three Rivers Wet Weather
- Pennsylvania water polluters map compiled by the New York Times utilizing EPA information
- The Clean Rivers Campaign, a regional effort promoting substantial investment in green infrastructure as part of ALCOSAN's strategy