Inflow and Infiltration FAQ

Inflow & Infiltration – Answers to Frequently Asked Questions

Q.  What is Inflow and Infiltration (I/I)?
A.  Sanitary sewers in Clermont County are designed to convey only wastewater.  However, many of these “separated” sewers also convey groundwater and stormwater that enter through leaky pipes, improper storm drain connections, and other means. Excess water that flows into sanitary sewer pipes from groundwater and storm water is called inflow and infiltration, or I/I.
Inflow is storm water that rapidly flows into sewers via prohibited connections such as roof drain downspouts, foundation drains, sump pumps, and storm drain cross-connections, as well as through holes in manhole covers and larger defects in the sanitary sewer system.
Infiltration is groundwater that seeps more slowly into sewer pipes through holes, cracks, joint failures, and faulty connections.

Q.  Why is I/I a problem?
A.  Extra water in the sewer system is a problem for many reasons:
1)    It takes up capacity in the sewer pipes and ends up at the wastewater treatment plants where it must be treated like sewage, resulting in higher treatment costs (and potentially higher rates to our customers).
2)    Requires new and larger wastewater facilities, such as larger diameter pipes and pump stations, to convey and treat larger volumes of flow, resulting in higher capital expenditures and potential rate increases.
3)    I/I flows contribute to sewer system overflows into homes and local rivers, streams and lakes, negatively impacting both public health and the environment.
Protecting the environment, decreasing wastewater treatment costs and maintaining affordable rates for our customers are some of the benefits of a regional I/I control program.

Q.  What is the Clermont County Water Resources Department Doing to Find Sources of I/I?
A.  The Water Resources Department uses several methods to identify sources if I/I.  These methods include flow and rainfall monitoring, closed circuit television (CCTV) inspections, smoke testing, dye testing and manhole inspections.
1.    Flow Monitoring: The Water Resources Department has multiple, portable flow meters which are installed at key locations in the sanitary sewer system.  The flow meters are programmed to continuously collect level, velocity and flow data at 15-minute intervals. Information collected from the flow meters is compared to rainfall data collected from various rain gauges through the county to determine levels of inflow and infiltration.  By strategically locating the flow meters, the Water Resources Department is able to pinpoint significant sources of I/I.
2.    Closed Circuit TV inspections record conditions using a TV camera within the pipes. A robotic camera is lowered into a sanitary sewer through a manhole, and then records a video while traveling the length of the sewer.  The video can identify cracks, fractures or breaks, root intrusion, leaking water (especially infiltration from groundwater), and general deteriorating conditions. The Water Resources Department also has CCTV equipment that can send a camera from the sewer main into a tap to inspect individual laterals from the main to the edge of the public right-of-way or public sewer easement.
3.    Smoke testing involves pumping smoke through sewers from manholes in streets and observing where smoke exits. The exiting smoke can indicate a broken pipe or identify where roof or foundation drains are improperly connected to the sewer system.  During the testing, smoke will typically appear from roof drains, catch basins or yard drains connected to the sewer system. The smoke may also appear from cracks in the pavement above the sewer, from landscaping above private connecting sewers, and around homes with foundation drains connected to the sewer. Under some conditions, smoke may also appear in basements through unused floor drains, disconnected or faulty plumbing fixtures, and other direct openings to connecting sewers.  At least 48 hours prior to testing, residents in the area are given notice that smoke testing will be conducted, as are local fire and police departments. Smoke should exit the sewer only through naturally vented openings, such as house roof vents.  It should not exit through properly sealed lines or trapped drains in the house.  Residents are instructed to pour water in all floor drains and trapped drain lines to ensure a good seal. This is especially important for drains that are in areas of the home that are not accessed or used frequently. The smoke, manufactured for this purpose, leaves no residuals or stains and has no effects on plant and animal life, and creates no fire hazard.  If smoke enters the home, it can be vented by opening doors and windows.  The inspection team is available at test sites to answer questions during the smoke testing.
4.    Dye Testing involves pouring non-toxic fluorescent colored dye down roof drains or catch basins to see if that dye makes its way into the sewer. This provides verification that the storm drainage being tested is directly connected to the sewer.
5.    Manhole inspections are a relatively inexpensive and quick method of detecting inflow/infiltration sources.  Visual manhole inspections can be used to identify any defects in the manhole bench, wall, rings and risers that would allow I/I to enter the system.  Inspections can also determine if surface water can pond or flow over the manhole and enter through vent holes in the lid.
Q.  How does Clermont County Eliminate Sources of Inflow and Infiltration?
A.  Once an I/I problem has been identified, there are many methods and technologies available to reduce I/I. One primary method focuses on fixing the broken pipes, manholes, and joint connections. Another focuses on reducing the amount of I/I that enters the sewer system from storm events by disconnecting roof drain downspouts and other building or yard drains that may be directly connected to the sewer.
Trenchless technology pipe repair methods may include pipe bursting, or cured-in-place pipe (CIPP). Pipe bursting is a technique that pulls a hardened steel breaker head through the old pipe, breaking it up, and replacing it with a new pipe all in one process.
CIPP repair involves pulling a resin-saturated liner through a damaged pipe which is then cured to form a tight-fitting, jointless replacement pipe. Trenchless repair methods require less digging than traditional “dig and replace” repair methods and minimize damage to yards and landscaping.

Stormwater connections such as roof drain downspouts, yard drains, and sump pumps are prohibited, and it is the responsibility of the property owner to disconnect these from the sewer system.  Water Resources Department personnel are available to provide guidance to property owners that need to eliminate any of these connections. Customers should call (513) 732-7970 if they desire assistance.

Q.  What Can I Do to Help Eliminate Sources of I/I and Avoid Blockages?
A.  Here are some things you can do to help reduce inflow and infiltration in the sewer system, all of which helps to reduce the risk of basement backups and overflows, the need to build larger pipes and pumps, the cost to convey and treat clear water mixed with wastewater, which in turn helps us to keep rates affordable for our customers.
1.    Inspect your roof gutters and downspouts to see if they are connected to the sewer system. If so, have them disconnected.  Downspouts may be directed onto lawns or garden beds.  They should be extended at least five feet from the foundation of the home.
2.    If your home has a sump pump, make sure it is not connected to the sanitary sewer system. If it is, it must be disconnected.  Like downspouts, sump pump discharges can be directed onto lawns or flower beds, and should be at least five feet from the foundation of the building.  Discharges from sump pumps can also be tied into separate storm sewers if there are any in the area.
3.    Keep your building sewer in good connection. Broken building sewers from the home to the edge of the public right-of-way or the start of the public sewer easement are the responsibility of the property owner. Keep the line clean and do not plant bushes or trees on top of it. Make appropriate repairs and replace if necessary.
4.    Install a cleanout in case you or your plumber need quick access to clear a blockage or stop a back-up.  Always keep a cap on the cleanout to keep out storm water and debris.
5.    Prevent grease buildups by not pouring grease and fat down the drain.  As it cools, grease and fat solidifies and can create a blockage.  Instead, pour grease and fats into a solid container and place it in the garbage.
6.    House building sewers often can become deteriorated or clogged with tree roots, which can result in a blockage that causes a back-up of sewage into your basement. It is important for homeowners to have their lateral inspected from time to time for roots.
7.    Do you have a house built before 1972? If so, you may have active foundation drains that are connected to the sanitary sewer.  Such connections are prohibited and must be eliminated. If your home was built and served by central sewers prior to 1972, financial assistance may be available to you to help with the disconnection.  Call the Water Resources Department at (513) 732-7880 to learn more about this program.