Questions about the tunnel project? Start here.

The regional tunnel system is a critical component of the Clean Water Plan (CWP), which was adopted to meet the requirements of the Federal Modified Consent Decree and improve and protect the water quality of the region’s streams and rivers.

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No, the tunnel system is adding new conveyance capacity to deliver combined sewage flows during wet weather events to the ALCOSAN wastewater treatment plant for treatment. The existing municipal and ALCOSAN sewers will continue to be utilized to transport sewage to the ALCOSAN wastewater treatment plant.

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The new tunnel system is designed to last for at least 100 years. Operation and maintenance staff from ALCOSAN will be responsible for maintaining it. The tunnels will be accessed for maintenance via the access shafts.

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Capturing “all” the overflows would not be affordable for the region. The tunnel system is configured and sized to capture enough of the combined sewer overflows to meet water quality objectives. The size of the tunnels was established in collaboration with the regulatory agencies.

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The CWP and the tunnel system is not intended to stop existing flooding conditions in the communities. The primary goal of the CWP and the tunnel system is to improve and protect the water quality of our rivers and streams.

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Subsidence is not a concern along the ALCOSAN tunnel alignment because the tunnels will be located deep in bedrock.

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ALCOSAN is a ratepayer-funded authority and most of the costs will need to be borne by the ratepayers. ALCOSAN’s rate strategy manages CWP cost impacts to ratepayers by implementing multi-year rate increases through 2036. ALCOSAN’s Board of Directors implemented a 7.0% annual rate increase for 2022 through 2026. Starting in 2022, the cost of ALCOSAN wastewater treatment and conveyance services was around $549 per year for a typical residential customer, or about $1.50 per day. The municipalities typically also have charges to support the local sewer services. ALCOSAN is currently updating its overall cost estimates for both the tunnel system and the Clean Water Plan based on recent bid results. These updated costs are being incorporated into ALCOSAN’s new multi-year rate structure, which will be released in late 2026. ALCOSAN acknowledges the impacts of rate increases on low-income households and has increased the Clean Water Assistance Fund to $40/quarter. More information on the Clean Water Assistance Fund can be found at dollarenergy.org.

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Sites will be restored to the existing condition at a minimum but may also be improved. Limited above ground facilities will be required as ALCOSAN will use the sites mostly to access the shafts and regulators via hatches and covers. As the design and construction of each tunnel progresses, ALCOSAN works with the community to determine potential opportunities for site enhancement following construction, which may include a paved surface or a cleared site for a greenspace.

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The new tunnel system must be constructed near existing sewers pick-up points to capture combined sewer overflows. This is a key factor in deciding on location of the proposed facilities. Other decision factors include environmental studies and geotechnical investigations.

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Email ALCOSAN at tunnels@alcosan.org with questions or comments about the regional tunnel system, including the Ohio River Tunnel.

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Construction at each tunnel construction site is anticipated to last between 2 to 5 years. Overall, the program will span 15 years.

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Several shafts will be in construction at the same time to meet the construction schedule, although not necessarily all.

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It is anticipated that the soil and rock from the shafts and tunnels will be trucked to landfills or other appropriate locations for proper disposal.

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Dust control is part of the overall erosion and sediment control requirements. The contractors will be required to monitor, control, and mitigate construction-generated dust. Mitigation measures may include water mist, covered stockpiles, street sweeping, and suspending construction activities in very windy conditions

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In general, the depth of the tunnel and the construction method in rock mean that noise and vibration would not be noticeable at the surface. ALCOSAN and its designers will include specifications in the contract documents to limit noise and vibrations around the shaft and near surface facility construction sites.

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The tunnel contractors will be required to monitor, control, or mitigate volume of construction activities sounds in accordance with local regulations. ALCOSAN, its designers and contractors will follow industry standards and best practices in terms of working hours, noise control measures and monitoring. Noise control measures may include equipment siting, acoustic screening, choice of routes for transport and hauling, and scheduling of activities/working hours.

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In general, the depth of the tunnel and construction method in rock mean that vibration would not be noticeable at the surface. For construction of the shafts, ALCOSAN and its designers will include specific requirements in the contract documents to prevent vibratory impacts to existing structures as well as monitor ground movement and vibration.

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Construction is anticipated to have some traffic impacts; these impacts will vary greatly depending on construction sites. ALCOSAN is preparing a Maintenance and Protection of Traffic Plan for each site to minimize traffic disruptions and obtain necessary approvals. In general, ALCOSAN will work with the contractors to minimize the use of local roads to quickly reach the highways. During construction, ALCOSAN will be providing advance notice of potential impacts, construction alerts via various media, and information on alternative routes required per the Maintenance and Protection of Traffic Plans.

To hear about impacts near you:

• Closures & Impacts lists current and upcoming road closures, lane restrictions and detours.
• Sign up for email updates and choose the tunnels you want to hear about — construction alerts come to your inbox.

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During construction, the sites will be fenced off to limit access to the construction site. After construction is completed access to the shafts will be limited to manhole structures like typical sewer systems.

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ALCOSAN has identified major community groups along the alignment and has contacted them for outreach and engagement. We are also working with the municipalities and elected officials along the tunnel alignment. We will be talking with the community organizations throughout the design and construction process. If you represent a community organization and would like to have ALCOSAN present at one of your community meetings, please email us at tunnels@alcosan.org.

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ALCOSAN has had a strong scholastic program for many years and will be working on integrating information regarding the regional tunnel system into the program.

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The main challenges are covered in the construction questions below — schedule, noise, vibration, dust, traffic and how spoil is removed.

Read the Construction Schedule and Impact questions

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ALCOSAN does not anticipate any building restrictions above the tunnel due to its depth. Subterranean easements will be needed along the tunnel alignment, but this will have no impact on surface activities and the landowners’ ability to sell or develop their land. The only development restrictions will be above the shafts/regulators as ALCOSAN will need continued access to these structures. If repairs are needed on the tunnel, ALCOSAN would access the tunnel through these locations.

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Some property acquisitions and easements will be needed beyond the property ALCOSAN currently owns. Eminent domain is not the preferred option and ALCOSAN has been working with property owners on an individual basis through its property acquisition team.

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A 2026 study by the Allegheny Conference on Community Development estimated that the regional tunnel system would support approximately 1,760 jobs annually. These jobs have been and will continue to span various sectors, including jobs in engineering and construction, but also local businesses such as restaurants and hotels.

ALCOSAN will not be hiring directly for construction work; the workforce will be hired by prime contractors and their subcontractors for each tunnel project or subproject. Contractors are anticipated to work with the local trade Unions per ALCOSAN’s Labor Stabilization Agreement, including laborers, operating engineers, electricians, carpenters, and teamsters. ALCOSAN has been proactive at advertising the project with engineering firms and contractors, including regional, local, and minority or women disadvantaged business enterprises (MBE/WBE). In general, the construction sectors that will be involved include:

• Tunnel work
• Building demolition
• CAD services
• Concrete supply
• Environmental testing
• Equipment rental
• Fencing
• Instrumentation and controls
• Landscaping
• Materials testing
• Mechanical and electrical work
• Office trailer set up
• Painting
• Permitting support
• Plumbing work
• Printing
• Security services
• Signage
• Site improvements (paving, concrete flat work, curb and gutter)
• Specialty welding services
• Structural concrete work
• Traffic control
• Trucking
• Utility relocation and construction (water, sewer, etc.)
• Vendors (fuel deliveries, tire repair services, trash hauling, janitorial services, safety supplies, welding supplies, sanitary services)

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The main challenges are covered in the construction questions below — schedule, noise, vibration, dust, traffic and how spoil is removed.

Read the Construction Schedule and Impact questions

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It is ALCOSAN’s policy to award a fair share of contracts to minority and women's businesses. The goal is that ten to twenty-five percent (10% to 25%) of all dollars relating to ALCOSAN contracts be awarded to minority or women's business enterprises. ALCOSAN will make every effort to meet that goal in its contracts as well as encourage that goal among its contractors, suppliers and their subcontractors.

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Job opportunities associated with the construction of the tunnel system are anticipated to come mostly from the contractors and subcontractors. See “How many jobs will be created? In what sectors?” FAQ for additional information and ALCOSAN-led activities.

Information about job opportunities at ALCOSAN can be found at https://careers.alcosan.org/.

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Making the City and surrounding municipalities more resilient to climate change is not the primary goal of the CWP and/or the tunnel system. The primary goal of the CWP and/or the tunnel system is to improve and protect the water quality of our rivers and streams. See FAQ: Won’t climate change and increased rainfall impact the tunnel system performance and cause additional overflows? Was this considered? Could the system be constructed and then found to be “too small”?

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Since ALCOSAN is not party to the municipal orders, this question is best answered by your municipality. ALCOSAN is fully committed to working collaboratively with your municipality to ensure the municipality has a full understanding of the ALCOSAN program. The current municipal orders allow for the municipalities to take credit for the projects that ALCOSAN has committed to in the Modified Consent Decree through 2036.

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This possibility was evaluated as part of the CWP. It was concluded that replacing the tunnel system using green infrastructure and source control would not be feasible given the volumes of overflow reduction required to meet the water quality objectives and completion schedule.

The regulatory agencies agreed that ALCOSAN should move forward with the tunnel system while continuing to invest in GSI and source control through our GROW program and gave more time to ALCOSAN to do so. The information to be collected through the GROW program must be continuously analyzed by ALCOSAN to evaluate the potential impact on the tunnel system and make relevant adjustments.

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For compliance with EPA’s CSO Policy and ALCOSAN’s Consent Decree, the tunnel system must be designed to achieve a specific performance level during a typical year rainfall as defined in the CWP. The typical year rainfall is based on historical data, consistent with the EPA’s guidance. While the tunnel is being designed to typical year conditions, the tunnel system will capture additional flows during years with higher than typical year precipitation totals.

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In general, the tunnel system once constructed is anticipated to improve aquatic biodiversity by reducing combined sewage overflows and improving overall water quality. The design will incorporate biodiversity mitigation measures as part of the permitting process where needed.

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The potential presence and protection of cultural resources is an important consideration for the ORT project. As part of the project permitting process, ALCOSAN has been working diligently with the State Historic Preservation Office to identify such potential historic properties so that any potential adverse effect can be identified and mitigated as part of the project specifications. Several listed or eligible properties, including the Western State Penitentiary, the D.L. Clark Building and the St Wenceslaus Church Complex, have already been identified. These project considerations and evaluations are dealt with through a formal consultation process initiated in early 2024.

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There will be several areas impacted by the construction of the ORT.

O27 Westhall Street: Trail access to be temporarily relocated during construction.

O41 Belmont Street: Trail access to be temporarily relocated during Belmont Street combined sewer replacement/relocation. Belmont Street will be closed during existing combined sewer relocation.

A58 Madison Avenue: Trail access to be temporarily relocated during temporary sewer installation at River Avenue and Madison.

A58 Voeghtly Street: Trail access to be temporarily relocated during installation of flap gate at rivers edge south of Voeghtly.

Additional details on closures and detours will be made available on ALCOSAN’s website and through informational sessions as the construction progresses.

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Yes - ALCOSAN works with the municipalities to develop detour plans for any trail closures as part of the project permitting process. ALCOSAN also engages with Riverlife and Bike Pittsburgh to reduce the impact on the trails as much as possible.

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ALCOSAN adjusted the ORT tunnel’s alignment in the final design process’s early stages based on site conditions and other criteria. The alignment is now set.

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The proposed locations are driven by the existing sewer outfalls, whose flows are directed to the tunnel system. Like the tunnel alignment, the preliminary location of the shafts and regulators was established as part of Preliminary Planning in 2017-2020 and was solidified during the early stages of final design.

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The final construction sites are defined during the final design of each tunnel project. The tunnel construction activities will mainly take place at the primary tunnel construction shafts. The only surface disturbances between the upstream and downstream tunnel construction shafts will be at the intermediate drop shaft or access shafts and along the consolidation sewers.

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Impacts on local roads were determined during the final design process. Traffic control plans were also developed as part of the design. Details on closures and detours will be made available on ALCOSAN’s website and through informational sessions as the construction progresses.

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