Inflow is water from rain and snowmelt that drains directly into the sanitary sewer system. Typical sources are from private property through sump pumps, roof drains, eavestrough downspouts and foundation weeping tile drains connected to the sanitary sewer instead of the storm sewer.
Inflow and Infiltration
The Municipality’s sewer system is comprised of two parts: storm sewers and sanitary sewers. Storm sewers properly manage excess water from rainfall, snowmelt or run off before discharging it to lakes and rivers. Sanitary sewers carry wastewater from toilets, sinks and drains to treatment plants for processing before returning it to the environment.
What is inflow and infiltration?
Inflow and infiltration is water that should be entering the storm sewer system makes its way into a sanitary sewer. This can be caused by damaged sewer pipes and/or incorrectly connected sump pumps, downspouts, and building drains.
Why is inflow and infiltration a problem?
When stormwater gets into sanitary sewers, it creates costly and disruptive problems:
· Reduce the capacity of sewage treatment plants, leaving less capacity for existing residents and future growth.
· Higher sewage treatment costs because sewage treatment plants will be required to treat a higher volume of flow.
· Will overwhelm sanitary sewer pipes and pumping stations, resulting in raw sewage discharging into local water ways, negatively impacting public health and the environment.
· May cause sewage backups in basements.
What you can do to prevent inflow and infiltration.
A single downspout can collect a surprising amount of water - up to 360 litres per minute during heavy rain. With multiple downspouts and foundation drains, one property can add significant inflow to the sanitary system.
There are a few things you can do to ensure your property doesn’t contribute to inflow and infiltration.
- Ensure your building drain or sump pump is not connected to the sanitary sewer system
- Ensure your downspouts flow onto your yard, or into a french drain or rain barrel
- Clear debris such as leaves and garbage blocking storm sewer grates
- Participate in inflow and infiltration reduction projects happening in your neighbourhood
Doing these things can help safeguard your property and protect the environment by reducing the likelihood of wastewater spills.
What is the Municipality doing about inflow and infiltration.
Finding and reducing inflow and infiltration is a high priority for the Municipality. It reduces sewage treatment costs, reduces wear on costly infrastructure and maximizes the capacity for wastewater to move through the system.
Inspection, Identification and Enforcement
In areas where higher-than-normal wastewater flows have been identified, the Municipality will use different techniques to pinpoint the sources. Residents will be notified prior to any testing in their area.
Sewer Cameras - A CCTV camera is inserted into the sewer pipe to identify cracks and failed pipes.
Smoke Testing - A harmless, odourless smoke is pumped into the wastewater sewer system. The smoke travels through the system and exits out any improperly connected eavestroughs.
Dye Testing - A harmless dye is added to the storm sewer to determine if there is a direct connection to the wastewater sewer.
As sources of inflow and infiltration are identified, Municipal staff will work to find the best way to correct them. The Municipality will address any issues in the sewers that are owned by the Municipality, while homeowners will be responsible to correct any issues on their own property.
Frequently Asked Questions
Infiltration is groundwater that leaks into the sanitary sewer system through cracked, faulty or broken sewer pipes. These pipes may leak because of poor installation, ground movement, and heavy vehicle traffic above the sewer or degradation of sewer piping.
High groundwater or water in the soil after rain or snowmelt could infiltrate private sanitary service lateral or mainline sewer, pipe joints and other parts of the sanitary sewer system that may have deteriorated, cracked, sagged, or collapsed. This water seeps into the system from the surrounding soil.
Trouble Signs of Inflow and Infiltration in the System
When all the extra storm water from inflow and infiltration flows into the sanitary sewer system, problems occur that can increase the cost for all residents and places an additional burden on the Municipality’s infrastructure and treatment facilities.
Examples of trouble signs of Inflow and Infiltration are:
· Greater than anticipated sanitary sewer flows measured at sewage treatment facilities.
· Raw sewage overflows or bypasses at sewage pumping stations.
· Surcharging of pipes and manholes resulting in a loss of capacity.
· Basement backups during and after rainfall events.
Reducing extraneous storm water flows from the sanitary sewer system will help address health, environmental and financial issues associated with overloading the sanitary sewer system.
There are three major consequences of too much storm water entering the sanitary sewer system:
1. Cost - Storm water does not require the same level of treatment as sewage does. However, when storm water enters the sanitary sewer system, it must be handled in the same manner as sewage; it must be transported, pumped, and treated, which costs water and sewer rate payers extra money.
2. Overloading - An improperly connected sump pump or storm drain into the sanitary sewer system delivers a much higher inflow of water during a storm. This may overload the sanitary sewer system and increase the risk of a sewage backup into individual homes and basements.
3. Environmental Impact - Overflows of untreated raw sewage at pumping stations has a negative impact on the local environment that all residents share and enjoy.
What can an individual resident do to Reduce Inflow and Infiltration?
Inflow and infiltration is consuming a large amount of the existing available sewage treatment plant capacity. Here are some tips for residents to assist in reducing Inflow and Infiltration and restore this lost treatment capacity:
1. Disconnect Downspouts - Rainwater runs off a roof, flows through the eavestroughs and downspouts and should discharge onto the ground on your property. The downspout should not be connected to a pipe taking it directly to the sanitary sewer system. During heavy rainfall, if the downspout is connected directly to the sanitary sewer system the sewers may become overloaded, increasing the risk of basement flooding, releasing polluted rainwater into our local waterways and sending unneeded water to our sewage treatment plants for treatment. Disconnecting your downspouts will help reduce the amount of stormwater sent through the sanitary sewer system. If you are unsure if your downspout is connected to the Municipal sewer system, contact the Environmental Services Department (519) 235-0310, extension 230 and they will arrange to have your connections checked.
2. Disconnect Sump Pumps - Sump pumps are designed to capture surface or ground water that enters basements or crawl spaces and pump it away from the house. The basic sump system includes drain tile, a sump pit, a sump pump, a float or switch, a drain line and a check valve. The sump pump pit extends below the basement slab and collects surface water that enters around the basement/crawl space foundation or groundwater that rises to the slab. Sump pumps should not be connected to the wastewater collection system. Sump pumps should drain into the Municipal storm sewer through one of two methods: a direct connection (a pipe from the house to the main storm sewer line), if available, or directly onto the ground (preferably 10-20 feet from the house and not directed into a neighbour’s yard or over a sidewalk).
3. Use Less Water - Using less water, keeping rainwater on your property and managing what and how much goes into our storm sewer system means you are protecting your home and the environment at the same time.
4. Recognize - Sewer backup incidents and costs of treating sanitary sewage will be reduced only if everyone’s stormwater is kept out of the sanitary sewer system.
· Prevents clean water from being sent to sewage treatment facilities. This reduces energy usage, emissions and wear on the sanitary sewage infrastructure.
· Reduces the risk of raw sewage spills into our streams, rivers and Lake Huron.
· Reduces the Municipality’s cost to treat sewage, keeping it affordable for all users.
· Reduces the risk of basement flooding.
· Opportunity to use a rain barrel — saving you money on your utility bill.
How can I identify an illegal downspout connection?
If your downspout is connected to the sanitary sewer (either directly or indirectly) it is illegal and is in contravention of the Municipality’s Sewer Use By-law and the Ontario Building Code.
If you suspect you have an illegal downspout connection, contact your local plumber to have it disconnected and properly re-directed onto your lawn, allowing rainwater to naturally soak into the ground.
How can I identify an illegal sump pump connection?
If your sump pump or foundation drain is connected to the sanitary sewer via a floor drain, laundry tub, sanitary cleanout or other direct or indirect connection, it is illegal and is in contravention of the Municipality’s Sewer Use By-law and the Ontario Building Code.
If you suspect you have an illegal sump pump connection, contact your local plumber to have it disconnected and properly re-directed onto your lawn, thereby allowing rainwater to naturally soak into the ground.
Some older homes have foundation drains directly connected to the sanitary sewer and do not have an internal sump or sump pump. There is also a possibility that your home may not have a foundation drain at all. To verify if you are in compliance with the Sewer Use By-law and do not have an illegal connection, contact a local plumber to complete an investigation. If an illegal connection exists, a plumber will be able to advise you on the best approach to make your home compliant with the Sewer Use By-law.
Who can I contact to fix my connection?
The Municipality does not fix downspout, foundation drain and sump pump connections. Property owners may complete the repair themselves, or they can contact a licensed plumber to complete the work.
What happens if I do not correct an illegal connection?
If the Municipality determines you have an illegal connection, you will receive written notice advising you that you have 30 days to repair it. Staff will conduct an inspection to determine if you have made the necessary correction
Do I need to install a sump pump if I do not have one?
No, you are not required to install a sump pump if you do not already have one.
Can I have a by-pass valve on my sump pump discharge hose?
No, it is illegal to have a by-pass valve on your sump pump discharge pipe or hose. Existing valves must be removed.
Where can I run the sump pump hose?
You should run your sump pump hose at least 6’ - 10’ away from your house to avoid “recycling” water back into the house; or connect to a storm service (if available). Avoid running the water directly onto your neighbour’s property.
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