Improving Our Community Waterways Together

FAQ

What is the Clean Water Act?
What is the Consent Decree?
What is a sanitary sewer?
What is a storm sewer?
What are (SSOs) sanitary sewer overflows and (CSOs) combined sewer overflows?
How big is the sewage overflow problem in our community?
Will sewage rates go up? I thought MSD was working on this sewage overflow problem already.
Is Louisville's problem unique, or are other communities facing similar problems?
What should I do in the event of a sewer overflow?
Are there health risks if contact is made with this contaminated water?
Aren’t the pipes that serve my house large enough to prevent flooding?
Why is this water a problem?
What is an improper connection to the sanitary sewer system?
What are different types of improper sanitary sewer connections?
Where should the water from downspouts, groundwater sump pumps, and/or other clear water sources be directed?
Why is it important for everyone to remove improper connections?
How can overloaded sanitary sewers cause basement flooding?
Do improper connections really contribute large amounts of clear water to the sanitary sewer system?
How does MSD identify the sources of clear water entering the sanitary sewer system?

What is the Clean Water Act? (back to top)
The Clean Water Act is the federal legislation that governs the introduction of contaminants and pollutants into waters of the United States. This Act has as its goals that all streams should be fishable and swimmable.

What is the Consent Decree? (back to top)
The Consent Decree is a legal document that is signed by both the community and an enforcement agency that binds the community to complete specific activities that will lead to the elimination or reduction of sewer overflows in their municipal sewer system.

What is a sanitary sewer? (back to top)
A sanitary sewer is a pipe located in the street or easement that is designed solely to transport wastewater from sanitary fixtures inside your house or place of business. Sanitary fixtures include toilets, sinks, bathtubs, showers and lavatories.

What is a storm sewer? (back to top)
A storm sewer is a pipe designed to carry rainwater away.  Storm sewers are normally much larger than sanitary sewers because they are designed to carry much larger amounts of water.  Drainage ditches and swales perform the same function in many neighborhoods.

What are (SSOs) sanitary sewer overflows and (CSOs) combined sewer overflows? (back to top)
A separate sanitary sewer system is designed to carry only wastewater to a water quality treatment center; a separate stormwater system is designed to carry only stormwater that is transported to ditches and streams. In a combined sewer system, both wastewater and stormwater are carried in the same set of pipes to the treatment plant. During nearly every rain, stormwater gets into these sewer systems, which results in untreated sewage overflowing into area streams and the Ohio River. When these overflows occur in the combined sewer system, they are known as CSOs. Likewise, when such overflows occur in the separate sanitary sewer system, they are known as SSOs. These overflows are generally caused by aging sewers or illegal stormwater and groundwater connections to the sanitary sewers and can contribute to water quality problems in our streams.

Diagram of a wet weather CSO

How big is the sewage overflow problem in our community? (back to top)
Louisville has over 3,200 miles of sewer, approximately 500 miles being over 100 years old. Much of the system is in need of rehabilitation or repair. Currently, there are 111 active CSO locations and on average will overflow 30 times per year. Additionally, during a year with above-average rainfall, over 100 locations in the separate sanitary sewer system could overflow.

Will sewage rates go up? I thought MSD was working on this sewage overflow problem already. (back to top)
Yes, sewer rates will go up to pay for the costs of rehabilitating our sewer system. However, it is MSD's goal to keep our sewer rates well below the national average as we have in years past. MSD has already spent more than $150 million over the past 5 years to reduce the impacts of CSOs and SSOs. Much improvement has been accomplished, but there is still much more to be done.

Is Louisville's problem unique, or are other communities facing similar problems? (back to top)
No, Louisville's problem is not unique. Wastewater systems across the nation, including many in our state, are facing the same problems of aging infrastructure and increasingly strict regulations. Many cities have already entered into similar enforcement actions, such as Louisville's Consent Decree. EPA has made it a priority to bring all cities with similar problems into compliance.

What should I do in the event of a sewer overflow? (back to top)
The most important thing to do is to stay away from water in ditches, streams and the river during and for 48 hours after rainfall. This is when overflows are most likely to occur. In the event of a sewer system failure, overflows may occur during dry weather. If you do come into contact with water that has been contaminated by a sewer overflow, you should wash with soap and warm water before touching any surfaces, persons or food.

Are there health risks if contact is made with this contaminated water? (back to top)
The health risks depends on how long and how much contact one has. For example, if contaminated water is swallowed while swimming, one might become ill and need to seek medical attention. If the contact is external - skin only - then a thorough washing with soap and warm water will be sufficient to kill any bacteria one has encountered. The best thing to do is avoid the contaminated water altogether.

Aren’t the pipes that serve my house large enough to prevent flooding? (back to top)
Most homes and subdivision are served by an 8-inch sewer pipe which is designed to carry sewage from 200 homes.  Many homes have sump pumps to keep dry and are supposed to be piped to discharge on the ground. However, if four basement sump pumps are connected illegally to a sanitary sewer they can cause a sewer overflow to occur.

Inflow and Infiltration
Inflow and infiltration are terms used to describe the ways that groundwater and stormwater enter the sanitary sewer system.

Inflow is water that is dumped into the sewer system through improper connections, such as downspouts and groundwater sump pumps.  (Sump pumps that pump only laundry water or other sanitary wastes are not a problem.)

Infiltration is groundwater that enters the sewer system through leaks in the pipe.
All of this water is called "clear water" (although it may be dirty) to distinguish it from sanitary sewage.

Why is this water a problem? (back to top)
Clear water belongs in storm sewers or on the surface of the ground, and not in the sanitary sewers.  When clear water gets into the sanitary sewers, it must be moved and treated like sanitary waste.  Too much clear water often causes sewer backups and overflows when it rains.

What is an improper connection to the sanitary sewer system? (back to top)
An improper connection permits water from sources other than sanitary fixtures and floor drains to enter the sanitary sewer system.  That water should be going to the storm sewer or allowed to soak into the ground without entering the sanitary sewer.

What are different types of improper sanitary sewer connections? (back to top)
Some examples of improper connections include downspouts, groundwater sump pumps, foundation drains, drains from window wells and outdoor basement stairwells and drains from driveways.

Where should the water from downspouts, groundwater sump pumps, and/or other clear water sources be directed? (back to top)
MSD's Wastewater / Stormwater Discharge Regulations and the Kentucky State Plumbing Code require this water to be diverted to storm sewers or above-ground drainage ditches.

Basement FloodingWhy is it important for everyone to remove improper connections? (back to top)
Removing improper connections will significantly reduce the flow of clear water to the sanitary sewer system.  This will reduce the possibility of basement flooding due to overloaded sanitary sewers and lessen the amount of water that has to be treated.

How can overloaded sanitary sewers cause basement flooding? (back to top)
The water in an overloaded sewer flows at a higher level than normal.  If the home has sanitary fixtures or floor drains that are below this higher, overload level, water can flow backward through the sanitary sewer lines into the basement.

Do improper connections really contribute large amounts of clear water to the sanitary sewer system? (back to top)
Yes, and here's why: An eight-inch sanitary sewer can handle domestic wastewater flow from up to 200 homes, but only eight sump pumps, operating at full capacity, or six homes with downspouts connected to the sewers, will overload this same eight-inch line.

Improper Connections

How does MSD identify the sources of clear water entering the sanitary sewer system? (back to top)
Sanitary Sewer Evaluation Studies (SSES) provide data to identify likely sources of I/I and to prioritize areas for repairs.  An SSES is an important tool for diagnosing the condition of the sewer system and determining what types of repairs might be necessary and successful.  The defects identified are often used with flow monitor data to prioritize areas for rehabilitation, construction, and maintenance activities.  The SSES process includes several tests and inspections that complement each other. There are four major methods: dye testing, television inspection, smoke testing and flow monitoring.

By flushing water and clothing dye into a suspicious downspout or sump pump, MSD can determine sources of clear water entering the sewers by the color of the water as it flows through the pipes.

By guiding portable television cameras through the sewer pipes, MSD can detect many of the sources of clear water entering the sewers.

By filling the sanitary sewer line with smoke and watching where it emerges, MSD can detect many more sources of clear water.  The smoke is kept from entering buildings by the drain traps required on all sanitary fixtures and drains.  It will emerge from the sewer stand-pipe vents on the roof of buildings — and from improper connections such as downspouts.  It may also emerge from holes in the ground that lead to leaks in sewer lines.

By inserting special measuring devices into the sewer lines, MSD crews can monitor the water flowing through them.  If the flow increases during rainstorms, it's a sure sign of infiltration.