Sewer Inspection Program

Sanitary Sewer Infiltration and Inflow (I&I) are presumed by most experts to be the primary cause of most sewer backups throughout the country. Backups and overflows occur when rain and ground water enter the sanitary sewer system, especially during storm events. This rain and groundwater overwhelms the design capacity of the sanitary sewer system and creates surcharges which result in sewage discharging into homes, streets, and streams.
 

Sewer Sanitary Inlfow and Infiltration

Sewer Sanitary Inflow and Infiltration
Infiltration occurs when groundwater seeps through damaged sewer laterals, connections between the laterals and the mains, or through cracks or separated joints in the sewers or manholes. While each infiltration source might allow a relatively small amount of water into the sanitary system the impact can be very substantial when multiplied by the thousands of homes connected to the system. Sources of inflow include downspouts, sump pumps, areaway drains or other outdoor drains improperly connected to the sanitary sewer. Inflow sources can be major contributor due to the volume of water associated with each source.

The City has been working to reduce infiltration throughout the public sewer mains and manholes utilizing a variety of methods. However, data indicates that a significant portion of the I&I in a typical sewer system actually occurs on private property. The diagram below demonstrates the common privately owned defects.

Frequently Asked Questions 
Why is the City doing this?
The City has created this free program to assess the extent of Infiltration and Inflow (I&I) which may be originating on private property in specific neighborhood that have a history of sewer capacity problems.  This information will help the City identify effective and appropriate remedies for the recurring sewer backups in these neighborhoods.

What do I get out of this program?
Homeowners will benefit from this free service by receiving a television inspection of their sanitary sewer lateral, as well as a general inspection of their site drainage conditions.  Sewer lateral repairs are often the most expensive emergency repair that a homeowner will face – typically costing more than $10,000.  The inspection will provide homeowners with an indication of the health of their drainage system and identify proactive measures to protect their home.

How long will the inspection take?
The inspection will likely take a couple hours.  The contractor will need access to all plumbing fixtures on the lowest floor of your home and any external drains or cleanouts. 

Will the Contractor repair any deficiencies?
Clover Contracting may provide cost estimates for any repair work identified, but homeowners are in no way obligated to follow the recommendations or to accept any services offered by the Contractor.

What will the City do with the reports?
The City will use the reports to estimate the amount and source of Infiltration & Inflow (I&I) which consumes capacity in our sanitary sewer system.  This will allow us to identify appropriate strategies for operating and managing the system.

What is Infiltration and Inflow?
Infiltration and Inflow (I&I) are common engineering terms used to describe how non-sewer water finds its way into a sewer system.  I&I are a frequent cause of sewer backups throughout the country and consume expensive sewer conveyance and treatment capacity.  Infiltration occurs when groundwater seeps through damaged sewer laterals, connections between the laterals and the mains, or through cracks or separated joints in the sewers or manholes. Sources of inflow include downspouts, sump pumps, areaway drains or other outdoor drains improperly connected to the sanitary sewer. 

Why is this program in my neighborhood?
The Hillwood and Oak Haven sanitary sewer basins have a history of isolated backups and overflows when rain and ground water enter the sanitary sewer system, especially during storm events.  This rain and groundwater overwhelms the capacity of the sanitary sewer system and creates surcharges which result in sewage discharging into homes and streets in the neighborhood.

What else is the City doing to prevent I&I?
The City has been working to reduce infiltration throughout the public sewer mains and manholes utilizing a variety of methods, including repairs to manholes, replacing pipes, and lining old pipes with fiberglass.  Unfortunately, a significant portion of the I&I in a typical sewer system occurs on private property.  Privately owned defects include private lateral pipes and direct connections of downspouts, area drains, foundation drains or sump pumps to the sanitary sewer system. 
 
Where can I learn more about the program?
The City’s Department of Public Works oversees the City’s Sanitary Sewer System.  Contact Matt Hansen via email at mhansen@fallschurchva.gov or by phone at 703-248-5298 (TTY 711).