Drainage Conflict - Surface Water

Surface water naturally flows downhill using whatever path it chooses. It may move as sheet flow, or flow through small rivulets or surface runs. Surface water does not flow in a defined channel of a natural watercourse. The courts have indicated that the flow of uncollected surface water onto an adjoining property is not grounds for a lawsuit. But the courts have also indicated that a lower property or downhill owner can protect their property from surface water flow by building berms or dykes, provided these are built on the lower property owner's property. The following questions are addressed:

What is surface water?

There are only two types of flowing water – surface water and watercourses. If water does not meet the definition for a watercourse, if litigated, a judge may decide that it is surface water. Usually, this is water that flows without a defined channel.

Surface water includes water that moves as a sheet across the surface of the land. It also includes private artificial systems constructed to collect surface water such as ditches, pipes, eavestroughs, etc. Surface water does not include municipal drains or award drains – these systems have been constructed under statute law.

Surface water

It's also easy to picture situations where surface water principles would apply.

Surface water

However, there are numerous situations where it is unclear if drainage disputes involve a natural watercourse or surface water.

Surface water

Surface water

What is natural flow of surface water?

Surface water may naturally flow across the ground and even form channels in the ground. Do not assume that all flowing water is a watercourse. Judges can treat surface water and watercourses very differently.

My neighbour has built a structure that is blocking surface water runoff from my land. What can I do?

The courts have indicated that a lower property owner has the right to protect their land from surface water flowing onto them from a higher property owner. Therefore, your neighbour may have the right to block this flow.

What is collected surface water?

Surface water naturally flows downhill using whatever path it chooses. If someone takes some action to concentrate the flow of surface water, this water is called "collected surface water". If you collect surface water, you have an obligation to discharge that water where it will not cause problems to downstream property owners. If the discharge of collected surface water causes problems or damages on downstream properties, this could be grounds for a lawsuit.

Examples of collected surface water include:

  • artificial ditches;
  • drainage from eavestroughs and downspouts;
  • water collected from the roofs of greenhouses;
  • discharge from storm water management ponds;
  • street curbs and gutters;
  • agricultural tile drainage systems;
  • road crossings.

What is a right of drainage?

As indicated in the "collected surface water" question above, a landowner can be held liable for damages for directing collected surface water onto a neighbouring property. However, if a landowner collects and directs surface water on lower land continuously, openly, peacefully, without being contested and without permission for 20 years, the landowner may have acquired a right to drain the water onto the lower land. Once a landowner obtains a prescriptive right, they cannot alter it. For instance, usually the landowner may not increase the amount of water that is flowing through to the neighbouring property or the boundaries of the drainage.

This right continues notwithstanding changes in property ownership for both landowners.

The time period to establish the right has been specified by the Real Property Limitations Act.

While a person can claim a right of drainage, that right does not exist until legal action is taken and the courts have ruled that the prescriptive right of drainage exists.

The courts have also indicated that a right of drainage exists for the conditions that created the prescriptive right. If the conditions are altered resulting in increased flow, the right of drainage may be lost. For example, a road crossing has drained onto the adjoining property for over 20 years and a right of drainage could be claimed. Recently, two new lanes were added to the road and now an increased quantity of water flows through the culvert onto the adjoining land. The right of drainage may have been lost.

My neighbour's surface water is draining onto my land. It doesn't seem that the surface water was collected. Do I have to accept this water? What can I do to resolve this problem?

You have the right to protect your property from surface water.

Options to take before taking any action not agreed to by your neighbour might include:

  • initiating discussions about a mutual agreement drain to solve the problem;
  • petitioning for a municipal drain to resolve the drainage problem;
  • consulting your lawyer about initiating an injunction as part of a lawsuit.

My neighbour has directed the downspouts of their eavestroughs onto my property. What can I do to resolve this problem?

A lower property owner has the right to protect their property from surface water. The neighbour's act of collecting the surface water may trigger a liability.

Options to take before taking any action not agreed to by your neighbour might include:

  • initiating discussions with your neighbour to solve the problem – the solution could be formalized with a mutual agreement drain;
  • petitioning for a municipal drain to resolve the drainage problem;
  • consulting your lawyer about initiating an injunction as part of a lawsuit.

The surface water off my property naturally drains onto my neighbour's property. Yet they have blocked the flow of water and it now ponds on my land. Can I sue them? What can I do to resolve this problem?

A lower property owner has the right to protect their property from surface water.

Options to take before taking any action not agreed to by your neighbour might include:

  • initiating discussions with your neighbour to solve the problem – the solution could be formalized with a mutual agreement drain;
  • petitioning for a municipal drain to resolve the drainage problem.

Our subdivision was built five years ago and there is a backyard swale (a very shallow channel) that drains each of the residential lots. My neighbour has filled in the swale on their property and has built a garden shed on it. The water now backs up onto my lot and it's constantly wet in my back yard. What can I do?

This problem may be governed by bylaws under the Municipal Act or agreements under the Planning Act. However, bear in mind that flow in the swale may be considered surface water, and your neighbour has the right to protect their property from surface water.

Options to resolve this problem might include:

  • a property standards bylaw under the Municipal Act to enforce this situation – check with your municipality;
  • an enforceable lot grading plan developed as part of the subdivision agreement under the Planning Act – check with your municipality.
If neither of these solutions are available, consider:
  • initiating discussions with your neighbour to solve the problem – the solution could be formalized with a mutual agreement drain;
  • petitioning for a municipal drain to resolve the drainage problem.

Can I block the flow of surface water?

The courts have generally indicated that a lower property owner has the right to protect their land from surface water flowing onto them from a higher property owner. Landowners may not enter their neighbour's land to block flow, but can take measures to block it on their own property.

Exercise extreme caution if you are considering this option. Although the courts have generally indicated that lower property owners have this right, legal action may still be initiated against them. Consult your lawyer before implementing this option, particularly if you are considering blocking surface water flow that originates from a road.

Remember that if surface water flow is blocked, the higher property owner can petition for a municipal drain forcing a drainage system through the blockage and across your land. Blocking the flow of water may not be a practical way to resolve the problem.


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 28 April 2011
Last Reviewed: 28 April 2011