What is Inflow and Infiltration?
Inflow and infiltration (I&I) is unpolluted water such as rain water, storm water, groundwater and water collected from foundation drains that enter the sanitary sewer system. This adds unnecessary strain and increases the costs for treatment at our wastewater treatment facility. Infiltration can occur in a variety of ways such as cracks or leaky joints in the sewer system or broken cleanout caps or deteriorated sewer laterals. I&I can also occur when water is directed from sump pumps or downspout drains into the sanitary sewer.
Why is clear water a problem?
Clear water entering the wastewater collection and treatment system create two main problems: First, it consumes system capacity. An 8-inch sanitary sewer can handle wastewater from approximately 200 homes. Only 18 sump pumps will consume the same capacity. If clear water is directed into the sanitary sewer and the capacity is ultimately overwhelmed, sewers can back-up into houses and overflow from manholes causing the release raw sewage into the environment. This creates health and safety issues that can be costly to resolve. Homes with sump pumps connected to the sanitary sewer system are more likely to be the first to experience a sewer back up in their home.
Second, clear water that reaches the treatment plant is treated unnecessarily. This increases the cost of treatment and adds to the wear and tear on equipment, reducing its life span. The added cost of treating this clear water is then passed onto the customers.
One last problem is that sump pumps connected to the sanitary sewer system is in violation of City Ordinance S-74-18 and plumbing codes. When it comes time to sell your house, it may be an issue during the inspection process.
What is the solution?
Sump pumps currently connected to the sanitary sewer system must be disconnected and rerouted to the storm water system. Water from sump pumps and gutters that discharges to the ground, must be located on your property, 25 feet away from any other property or easement line, whichever is more restrictive. The discharge must be onto a pervious surface, such as grass. If there is not 25 feet available, it must discharge as close to your home as possible. Splash blocks are acceptable in this situation to move water away from the structures foundation. Sump pumps may be directly connected to storm structures or to rear yard subsurface drains. The connection must be made by a licensed and permitted plumber and it must be inspected by the Engineering Department. For further questions or advice on acceptable discharge locations, contact the City of Carmel Engineering Department at 317-571-2441.
Sump Pump Inspection Program
To help our customers determine if their sump pump is incorrectly connected to the sanitary sewer system, Carmel Utilities is offering a free inspection program for our sewer customers. A Utilities staff member, at a mutually agreed time, will come to your home and inspect your sump pump. They will be able to determine if it is incorrectly connected and answer any of your general questions. They will not be able to do any work or give you advice that should come from a licensed plumber.
To schedule your inspection, please contact:
Partial Reimbursement Credit Program
Carmel Utilities offers a partial reimbursement credit program for our sewer customers in the event they have to redirect their sump pump or downspout to comply with the City Sewer ordinance. A customer who disconnects their pump or downspout and reconnects them in a proper manner is eligible for the following credits that will be applied to their Carmel Utilities bill:
|Source Description||Minimum Amount|
|Directly connected storm sump pump||$250 per single structure|
|Directly connected storm sump pump with diverter valve||$50 per single residence|
|Downspout or leader||$35 each|
|Cap/repair cleanout||$15 each|
- The total amount of credits issued shall not exceed $600 per structure or parcel of real estate.
- Credit will be given on the monthly Carmel Utilities bill.
- Final inspection must be done by a Carmel Utilities staff member to get the credit.
- Acceptance of credit shall constitute consent to a re-inspection of the premises within five years following the date of compliance verification.
For complete details about the sump pump financial assistance credit program and other sewer related information can be found on our Sewer Use Ordinance.
Get your copy of Your Guide to Sump Pump and Downspout Water Discharge.
Frequently Asked Questions:
What is a sump pump?
A sump pump is a mechanical device located in a sump pit in your basement or crawl space areas. Its purpose is to pump accumulated clear water from building foundation drains and downspouts to the storm water system.
Sump Pump Discharge
The sump removes water from the drain tile (a perforated pipe around the foundation designed to collect groundwater), which flows in to the sump pit. Once the water in the sump pit reaches a certain level, the sump pump starts and pumps the groundwater through the discharge pipe. The sump pump discharge should spill on to a splash pad or through a flexible hose to a drainage way or storm sewer. This will minimize soil erosion at the foundation wall and re-circulation of the groundwater to into the drain tile.
Is there a charge for the sump pump inspection?
There is no charge for inspections of sump pump connections.
What if it is found that I have an incorrectly connected sump pump?
If there are improper connections, you may be contributing to sewer back-ups and unnecessary water treatment costing the City and wastewater customers. You are also more likely to have a sewer back up yourself. If changes are needed, you will have up to 30 days to complete the changes and will be eligible for the cost reimbursement credit program upon final inspection.
What should I do to prevent I&I?
- Disconnect sump pumps from sanitary plumbing drains that discharge to the City’s sanitary sewer system.
- Maintain positive drainage away from your house foundation.
- Make sure discharges are not directed onto an adjacent property, sidewalk or street.
- Ensure that the lateral from your house to the mainline sewer is in good condition and not broken or cracked.
- Remember, the sanitary sewer system is designed to manage normal flows of wastewater, not rainwater or water from sump pumps or downspouts.
- Homeowners have an impact on preventing or exacerbating the problem of inflow. Your community is relying on you to for making sure that your connections are not contributing to the problem.