Manage grading and drainage on your property

Learn how to maintain good drainage on your property, how to deal with water on your property and solve issues with water flowing from neighbouring properties. The city does not intervene or mediate drainage dispute issues on private property.

View information about protecting our drinking water on the Stormwater management page.

On this page

  1. Work with your neighbours to prevent drainage issues
  2. Contact the city when drainage issues are caused by city-maintained stormwater structures
  3. Learn how grading protects your property
  4. Maintain proper water flow on your property
  5. Identify drainage features on your property

Work with your neighbours to prevent drainage issues

Most flooding and drainage issues are caused by changes you or your neighbours have made to your properties. Examples are: a pool, a side yard walkway, a retaining wall, a patio, a deck or changes to the property’s grading.

Drainage issues on your property may be caused by:

  • grading changes on property
  • new landscaping or improper location and installation of landscape features like a fence or flowerbeds
  • change in downspout or sump pump location or function
  • compacted soil
  • filled in or blocked side yard
  • blocked drainage swales
  • blocked private catch basin

Some ways to solve this issue are:

  • discuss the concern directly with your neighbour and let them know how the changes on their property are affecting your property
  • work with your neighbour to find a solution
  • review the condition of your property and see if any changes you made may have affected the runoff flow such as gardens, retaining walls and low spots in your yard
  • make a minor change to your property to help solve the problem
If these methods do not work, some individuals choose to live with water issues, some work as a group to solve the problem, while others pursue legal action.

Contact the city when drainage issues are caused by city-maintained stormwater structures

Contact the Utilities division using the Report an issue form when excess water on your property is caused by work on a construction site close to you, or from city-maintained stormwater structures such as drains, ponds or streams.

Be prepared to provide:

  • a date when the issue started
  • information about the impact on your property 
  • pictures of the problem

The city will not take action on calls about disputes between neighbours related to water on your property.

Storm drainage is one of the most common areas of neighbour disputes and the city does not intervene or mediate drainage dispute issues on private property because this is a civil matter. 

Common-law recognizes that the lower land must accept the naturally flowing surface water from higher land but surface water should not be directed by artificial means onto neighbouring properties. 

Learn how grading protects your property

Grading impacts where the water ends up on your property. Lot grading helps ensure:

  • that rain and snow melt flow away your home and other buildings on your lot
  • that water is directed to a better location such as a catch basin or a storm swale  
  • ponding of rain and snowmelt, settlement, damp basements, damp yards and disputes between you and your neighbours are prevented

Changes to the original approved grades or the historically existing grades on your property must not impact how water flows from your property to neighbouring properties.

Subdivision grading plans are designed to meet city standards and are stamped by an engineer. These plans ensure that water will flow away from homes as required by the Ontario building code to prevent ponding, basement flooding and to ensure the yards will drain properly. Each individual lot has a grading plan which provides even more detail regarding grading and drainage at the lot level. 

Once the city has approved the grading plan, the builder and/or developer is responsible for addressing drainage and grading issues, excluding homeowner modifications, for two years during a maintenance phase.

As a homeowner, you must:

  • be responsible for any modifications you make to your lot (even within the maintenance phase)
  • do regular lot maintenance to make sure that water continues to flow away from your foundation and does not impact neighbouring properties
  • talk to your neighbours when you make changes to your lot that may impact drainage. These activities may include pool installation, landscaping or other building activities.
  • consult an expert prior to starting any project that could potentially impact drainage

Maintain proper water flow on your property

If you alter your property and it changes the way surface water flows, it is your responsibility to take steps to correct the issue.

There are various regulations that place limits on alteration of property and construction. Some of these are controlled through a permit process, for example, pool and shed structure permit issuing, and others are regulated through the property standards bylaw.

Actions to take to maintain good drainage


  • ensure downspouts and sump pump outlets are not draining directly onto your neighbour's property or too close to the lot line
  • keeping drainage swales and catch basins as originally designed
  • keeping drainage swales and catch basins free of obstructions
  • ensure plantings, fences, landscaping, pools, or other features do not alter the drainage and impact other properties
  • consult an expert prior to starting any project that could potentially impact drainage
  • build a patio, walkway, or other hardscaping at least two feet (0.6 m) from any property line or drainage swale
  • keep fences at least 6 inches(15 cm) above the bottom of a drainage swale to allow water to pass under it
  • shovel off the snow in spring to allow for earlier drainage as the snow melts
  • talk to your neighbours on a regular basis about drainage maintenance issues and especially if you plan work that could impact drainage
Actions to avoid

Do not:

  • extend downspouts or other pipes to the property line or onto your neighbour’s property
  • fill a drainage swale with anything that could alter the flow of water (e.g., concrete, asphalt, rocks, soil or woody plants and trees)
  • raise or lower the grade of your yard. Changing the grade of your yard could potentially impact the flow of water on a neighbouring property.
  • use your fence as a retaining wall. Retaining walls should be at least 15 centimetres away from any property line. Retaining walls over 1m in height require a building permit.
  • build raised gardens or patios that could potentially impact flow of water
  • dump any liquid other than water anywhere on your yard
  • use materials that prevent surface water from soaking into the ground

Manage standing or excess water using landscaping, rain-scaping techniques, proper grading and maintaining your catch basin or stormwater drainage swale to reduce surface water getting into your home. Some of these techniques qualify for the stormwater credit program. View more information on the stormwater web page.

Drainage features on your property

Drainage features depend on correct grading to function properly. Any change to the elevation and property grading might affect not only the owner but also the neighbours. It is the homeowner’s responsibility to ensure their property is graded appropriately. A drainage feature collects, infiltrate, conveys, redirect or stores surface water or storm water runoff: such as a swale, a catch basin, a French drain.
When drainage features fall on the property line, the responsibility to maintain them is shared between neighbours.

Drainage caused by grading

Grading is when property is sloped to direct surface runoff from rain or snow water away from foundations. Grading in a subdivision directs the water on a lot to a safe place and eventually to stormwater management sewers or creeks.
It is important to understand which way your lot drains to maintain proper grading on your property, especially along shared rear and side property lines. This ensures that lot grading is consistent with the lot grading plans. You may have back to front drainage or split drainage on your property.

An illustration showing the direction of water flow on the lots of a subdivision

Image source: City of Guelph

Back to front drainage

The rear lot line is the high point on the lot forming a raised area (drainage apron). Surface water on the property is drained to side yard swales along the common side yard swales and out the front of the property toward the street.

Split drainage
The highest elevation is at the side of your house. Some surface drainage then flows to the street while the rest of it will flow to the back of your lot. Water that flows to the back will be collected in a swale or catch basin and then be discharged into a storm sewer.

Drainage swale

A swale: 

A photo showing a sloped area between two houses

  • is a shallow grassed drainage channel, depression or trough with gently sloping sides
  • collects and directs water during rain events away from the building foundation, towards nearest street, lane or catch basin
  • is typically located along property lines that separate lots and sometimes at the back of a lot
  • should not be fill in or block as this causes rain water or snowmelt to collect and pond on your property
  • must be maintained by the property owner
  • must not be blocked or drainage will be impacted

Window well

A window well:

A brown brick house has a basement window surrounded by a grey metal barrier

  • is a rounded metal or concrete wall installed around basement windows
  • is often above ground to allow for settling of a building foundation
  • allows the ground around the basement foundation to be raised to achieve proper slope away from the foundation
  • may need to be taller to prevent water from entering underneath and filling the well
  • along with windows, should be sealed and or replaced if leaking

Rear yard catch basin

A catch basin:

A grassy yard behind a row of houses sloping towards a rust coloured grate sticking from the ground

  • is a grated hole that leads to a stormwater sewer system
  • is located at low points along rear property lines
  • collects water runoff usually from a large area and directs it into an underground storm sewer
  • has a metal grate to allow water to enter while blocking leaves and other debris
  • is maintained by the property owner
  • must not be blocked or drainage will be impacted

Infiltration trench or gallery

It is an underground feature that helps to speed up the rate that water soaks into the ground. It is

  • generally found at the rear of a newer lot
  • formed by an excavation that is filled with gravel
  • a feature that may service one or multiple lots

Positive slope

A view of a brown brick house with a garden then a path and another garden. The highest point is next to the foundation and it the other features slope away and down.

Positive slope is the sloping away of soil from a structure that directs surface drainage away from a foundation and window wells, and reduces the volume of water flowing to the weeping tiles. It is:

  • formed by building up the ground around your house so that water flows away from your foundation
  • affected when the ground settles. Examine sidewalks, patios, decks and driveways and repair the settled slope when this occurs.