What Can You Do to Help Protect the Sewer System?
We can all make a difference to protect the sewer system. Sanitary sewer systems and wastewater treatment facilities are designed to collect and treat dirty water that has been used for toilet flushing, bathing and showering, washing clothes and dishes and other normal residential, business and institutional purposes. However, when certain items enter the sanitary sewer system, sewers can become clogged leading to sanitary sewer back-ups and sewer overflows into the environment. Below are simple actions you can take to help protect the sewer system:
- “Can the Grease”. DO NOT dispose of grease and oils into any sink or drain. Instead pour grease into a can, cool the can in the freezer, and then discard in the trash.
- Wipe grease out of pots and pans with a paper towel prior to washing. Place paper towels in the trash.
- Minimize use of garbage disposals as many foods are cooked or contain additional oils. Use strainers on sinks to catch food scraps and dispose of in the trash.
- DO NOT flush non-degradable materials down the toilet. These include items such as so-called “flushable” wipes, paper towels, condoms, and personal hygiene items (tissues, feminine care products, Q-tips, etc). Instead place these items in the trash.
- DO NOT flush medications down the toilet. Flushing medications into the sewer system pose a hazard to water quality. Instead, mix them with substances like kitty litter or used coffee grounds, place mixture in a seal-able bag, and place in a secured trash can. Alternatively, you can return these medications during Drug Take-Back Days or at permanent disposal locations. To locate a permanent disposal location, please visit the U.S. Department of Justice's Diversion Control Division website.
- Report any sanitary sewer issues to the City by calling 311 or 703.746.4311.
Sanitary Sewer Backups
More than 90 percent of the City by land area is governed by two separate sewer systems – one for sanitary sewage that conveys wastewater from homes and businesses to a wastewater treatment facility and one for stormwater that conveys runoff during rain events to nearby waterways. In the City's Old Town area, these two types of sewers are combined – or in the same pipe. In the separate sanitary sewer system, sewer backups into homes and businesses may occur during periods of heavy rainfall due to sources of stormwater entering the sanitary sewer pipe instead of stormwater pipes. In the combined sewer system, these backups may occur due to the capacity of the combined sewer pipe being exceeded.
How Does Stormwater Get into the Sanitary Sewer System?
Infiltration and Inflow, also known as I&I, can take up valuable capacity in the sanitary sewer system. Infiltration is groundwater that enters the sewer through cracks in both the City sewer pipes and later sewer pipes that connect sewage from homes and businesses into the City sewer pipe. It can also enter through cracks and voids in the sewer manholes as well. Inflow is stormwater that directly enters the sanitary sewer from multiple sources, both in the City right-of-way and in some cases from private property. The figure below provides a summary of the sources of I&I.
Initiatives to Address Sanitary Sewer Backups
The City is implementing a number of projects in both the sanitary and combined sewer systems to reduce the risk of sewer backups due to heavy rainfall:
Sanitary Sewer Asset Renewal Program
The City is implementing a Sanitary Sewer Asset Renewal Program, which will provide for the inspection and rehabilitation of all City sanitary sewers, manholes, and City-owned portions of lateral sewers. Click here to learn more about this program.
Manhole Insert Installation Project
The City is currently procuring a contractor to install 870 stainless steel manhole inserts. Manhole insert sit on top of the manhole underneath the manhole cover and prevent stormwater inflow from entering the manhole through the holes in the cover. Manhole inserts are one of the most cost-effective ways to reduce inflow from the sanitary sewer system. The figures below show where the inserts will be installed. It is anticipated that a contract award will be made in Spring 2023 and installation will commence in Summer 2023.
Sewer Upsizing Projects
There is a potential of reducing the impacts of sewer backups by increasing the capacity of the pipe through replacing the existing pipe with larger pipe. In FY2023, the City programmed $10.5 million for these kinds of projects, to be implemented in areas subject to repeated sewer backups. There are two projects currently identified:
300 block Ashby/500 block E Alexandria/0000-100 block E Maple/200-300 block E Oak, 100 block E Raymond. Project design is currently ongoing for a sewer upsizing project in multiple areas. Construction is anticipated to begin in Fall 2023. More information will be provided once design is complete.
300 and 400 block N Alfred Street. Project design is underway and anticipated to be completed Summer 2023 with construction to start in late 2023/early 2024. More information to be provided in the coming months.
Staff are currently working on a longer range, 10-year plan, that identifies other sewers for upsizing and will share this information here once available.
Combined Sewer Separation Projects
Separating out sanitary sewers from the combined sewer system and connecting into the sanitary sewer system is an effective way to mitigate sanitary sewer backups. Below is the status for current projects:
• 500 block N Pitt Street. This project has been completed. The Notice to Proceed for construction was provided in July 2022.
• 600 block N Columbus Street. A feasibility study was completed in early 2023 which recommends separating the northern half of the block from the combined sewer system and connecting to a separate sanitary sewer at Wythe Street. The City is currently working to procure engineering design services, with design to start in Summer 2023. it is anticipated this project will go to construction in Summer 2024.
Staff is currently working to identify the feasibility of other sewer separation projects and will update this page as feasibility studies are completed and projects move into the design phase.
What You Can Do
Backflow Preventer Reimbursement Program. The City offers a partial reimbursement program for residents who have a licensed plumber install a backflow preventer device on their sewer lateral. These devices can help protect against future backups. The amount of the reimbursement is 50 percent of the cost to install the device up to a maximum of $2,000.
Disconnect Private Sources of Stormwater Inflow from the Sanitary Sewer. Another way to mitigate sanitary sewer backups is to disconnect private sources of stormwater into the sanitary sewer or reduce the impacts of those sources. Two examples of these sources are downspouts (roof leaders) and outdoor basement stairwell drains. If you see that any of your downspouts discharge into the a pipe that goes into the ground or if you have an outside basement stairwell drain, and your home was constructed before 1970, there is a possibility they are connected to the sanitary sewer system. If you would like to find out if your downspout is connected to the sanitary sewer system, call us at 703.746.4014 so that City staff can help assess if they are connected to the sanitary sewer along with options for either disconnecting these sources or how to minimize their impact on sewer backups.
RiverRenew Program for the Combined Sewer System
The City’s combined sewer system dates back to the 1800s and comprises approximately 540 acres located in the Old Town area. During most wet weather events, combined sewage (a mixture of wastewater and stormwater runoff) discharges through one of four combined sewer outfalls into receiving waterways.
In April 2017, the Virginia General Assembly passed a new law requiring the remediation of these outfalls by July 1, 2025. The City, working with Alexandria Renew Enterprises (AlexRenew), submitted a Long Term Control Plan to the Virginia Department of Environmental Quality (VDEQ) in 2018.
This plan calls for the construction of an underground tunnel system to bring combined sewage to the AlexRenew wastewater treatment facility, thus significantly reducing both the number and volume of combined sewer discharges into City waterways. VDEQ has approved the plan and the City has transferred ownership of the combined sewer outfalls to AlexRenew. AlexRenew is implementing the plan as part of its RiverRenew Program.
To find out more information about the RiverRenew program, please click here.
Programs and Projects
City Council - AlexRenew Board Project Review Workgroup Subcommittee
To facilitate partnership between the City and AlexRenew, and to provide a liaison for input and feedback, this workgroup will review and guide the plans, design, implementation, costs and financing of the combined sewer construction project with the intent of minimizing community impacts and maximizing community benefits. The next City Council/AlexRenew Board CSO Workgroup meeting will be held on Wednesday April, 2023 from 6-7:30pm at Alexandria City Hall, 301 King Street, in the Sister Cities Conference Room 1101. For information about upcoming meetings and to learn more about the CSO Workgroup, click here.
Combined Sewer System Community Engagement
Building off the foundation from previous groups, the new RiverRenew Stakeholder Advisory Group (SAG) will monitor construction progress on the Tunnel System Project, the largest infrastructure project in Alexandria's history. The next RiverRenew SAG meeting will be held on Thursday May 18, 2023 from 7-9pm at AlexRenew, 1800 Limerick Street, 6th Floor. For information about upcoming meetings and to learn more about the RiverRenew SAG, click here.
Fats, Oils, and Grease (FOG) Program
The City has developed a Fats, Oils and Grease (FOG) program to reduce the amount of FOG introduced into the sanitary sewer system, which can lead to sewer back-ups and sanitary sewer overflows into the environment.
City Assistance Program For Sewer Backflow Prevention
The City of Alexandria offers assistance to homes that may have experienced a basement backup after a heavy rainfall and are interested in having a licensed plumber install a backflow preventer.
Sanitary Sewer Asset Renewal Program
The City is implementing a Sanitary Sewer Asset Renewal Program, which will provide for the inspection and rehabilitation of all City sanitary sewers, manholes, and City-owned portions of lateral sewers. A total of $36 million has been programmed over the next 10 years as part of the City's Sanitary Sewer Capital Improvement Program. The first phase of inspections included sanitary sewers generally bounded by Commonwealth Avenue, Four Mile Run, Route 1, and the Metro rail lines. Inspections for the first phase began in March 2021 and concluded in December 2021. Second phase inspections, west of Commonwealth Avenue, began in June 2022 and will take approximately 9 months to complete. Sewers and manholes that are found to either be structurally deficient will be rehabilitated, with a rehabilitation program scheduled to commence late 2022/early 2023.
Old Town Sewer Assessment and Rehabilitation Program
This project provides for the condition assessment of all sewers in the Old Town area (including the combined sewer area) of the City and remediation of structurally deficient sewers and sewer structures. This project will be completed in several phases, starting with inspections. The first phase of inspections was completed in June 2020 and consisted of physical inspections of all manholes and inlets in the Old Town area. This second phase of inspections was completed in June 2021 and included CCTV inspection of all sewers in the northern half of the Old Town area. Currently, CCTV inspections are ongoing in the southern half of the Old Town area, which are anticipated to be completed by June 2023. Once these inspections are completed, the rehabilitation phase of the project will commence.
Sanitary Sewer Geographical Information System (GIS)
There are over 240 miles of sanitary and combined sewers located within the City. Information about these sewers are available to the public on the City’s GIS Sewer Viewer.
The Sewer Viewer displays the sewer network, and includes information such as pipe diameters, flow directions and manholes.
About the Division
The Sanitary Infrastructure Division is responsible for:
- Planning level engineering encompassing over 240 miles of sanitary and combined sewer within the City
- Development and implementation of the City’s 10-year Sanitary Sewer Capital Improvement Program
- Coordination with the City’s Department of Project Implementation related to design and construction of sanitary sewer capital projects
- Coordination with Alexandria Renew Enterprises on the RiverRenew Program for the combined sewer system
- Review of development and redevelopment plans in order to ensure adequate sewer capacity to accommodate growth and identify when upgrades to sewer infrastructure are required to serve new development
- Ensuring that development projects located within the CSS comply with the City’s CSS Management Policy for development/redevelopment
For more information or questions, please contact 703.746.4014.