Inflow and Infiltration

a home owner standing in a flooded house

Reducing Inflow and Infiltration

Prevent sewage backups. Check downspouts drain to your yard and nowhere else.  

During storms, rain can enter the sewer system through downspouts connected to the system when they should not be. This can overwhelm the system, causing dirty water to back up into your basement through floor drains, toilets and other plumbing fixtures.

If your downspout goes directly into the ground, it may be connected to the sanitary sewer system. Protect your home by disconnecting and redirecting downspouts so water flows to your yard, at least 2 metres away from your home.

Homes built before 1986 are more likely to have downspouts connected to the sewer system - if your home is older, it is a good idea to check your downspouts drain to your yard and nowhere else. 

How to disconnect and redirect your downspout 
Downspout connected to sewer system

Correct Downspout Drainage

Only disconnect your downspout on your own if you can do so safely. Point it away from your home’s foundation and keep the flow directed away from your neighbour’s property.

If you are not able to disconnect your downspout, contact a licensed plumber, eavestrough professional or general contractor for help.

1. Find the connection

  • Look for where your downspout goes underground
  • Dig to expose the connection below the surface 

2. Cut and cap the pipe

  • Carefully disconnect downspout from underground pipe
  • Seal open pipe with a proper cap to stop rainwater from entering the sewer 

3. Add an extension

  • Attach a downspout extension or splash pad to make sure water flows at least 2 metres away from your home  

4. Choose a safe drainage spot

  • Let water drain onto your lawn, garden or gravel bed
  • Do not let water drain on to your neighbour’s yard  
  • Make sure the ground slopes away from your home so water flows away, not back toward your foundation 

Video on how to disconnect your downspout, courtesy of Milwaukee Metropolitan Sewerage District

What is Inflow and Infiltration and why is it a problem? 
water flowing into sewer system

Inflow and Infiltration (I&I) is water from the environment like rain and melted snow that gets into the sanitary sewer system through holes and cracks in pipes and outdoor drains connected to the system when they should not be.

This excess water takes up space meant for wastewater from homes and businesses and can overwhelm the system causing:

  • Costly sewage backups and basement flooding that damage property
  • Environmental risks from untreated sewage overflows
  • Higher costs for everyone to treat water that should not be in the system 


 

What can homeowners do to prevent inflow and infiltration? 

There are a few simple things you can do to protect your home and ensure your property does not contribute to inflow and infiltration.  

  1. Check downspout drains to your yard and nowhere else. If they go directly into the ground, they may be connected to the sanitary sewer system. Learn how to redirect your downspout so water flows on to your yard, away from your home
  2. Ensure sewer grates on your street are free from debris such as leaves and garbage to help storm water drain properly
  3. Fix cracks in your foundation and plumbing to prevent water from seeping in
  4. Participate in Inflow and Infiltration reduction projects happening in your neighbourhood

The infographic below explains the difference between an incorrect and properly-connected downspout: 

Correct and Incorrect downspout connections
What is York Region doing about inflow and infiltration?

York Region prioritizes finding and reducing inflow and infiltration. The Region monitors rainfall and the sewage system to find areas where extra water might be getting into the system. This helps save money, keep our infrastructure in good shape and ensure wastewater can flow smoothly through the system.

When we find a source of inflow and infiltration, we work with the local city or town to inspect and repair the issue.

The Region also proactively applies inflow and infiltration reduction practices to the design and construction of new sewer systems and rehabilitation projects, ensuring new infrastructure is watertight from the beginning. View full details on Inflow and Infiltration Reduction Standard for Sewers Servicing New Development. 

What local cities and towns are doing about inflow and infiltration

Aurora

East Gwillimbury

Georgina

King City

Markham

Newmarket

Richmond Hill

Vaughan

Whitchurch-Stouffville

Please visit your local municipality’s website to learn more about activities in your area.

What to expect when inflow and infiltration inspection or repair work is happening in your neighbourhood? 

Once a source of inflow and infiltration has been found, York Region and/or local cities and towns begin repair projects which may include:

  • Repairing defects such as cracks or holes in pipes
  • Disconnecting known inflow sources, such as downspouts from the sewage system
  • Reviewing and updating construction design standards
  • Developing new standards and guidelines for inspecting and testing the sewage system

Trenchless technology is used to repair or replace pipes with minimal digging or disruption to property. Examples of trenchless technology include:

  • Pipe bursting - Replacing an older pipe by sending a new pipe through the old one and “bursting” (destroying) it from the inside
  • Relining - Creating an epoxy lining inside of an existing pipe
  • Cured-in-place pipe - Creating a pipe within an existing pipe

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