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Flood information

Flood information

Current situation

City staff continue to monitor conditions in communities that have experienced flooding in the past.

If you see significant flooding in your area please call 3-1-1.

For information on water levels, see the following websites: Rideau Valley Conservation Authority, the South Nation Conservation Authority, the Mississippi Valley Conservation Authority, the Ottawa River Regulation Planning Board and the Ontario Ministry of Natural Resources and Forestry. 100-year flood plain map

Also visit the Residential Flooding page on

Tips to prevent basement flooding

Residents can help prevent basement flooding with a few simple changes around the home:

  • Seal window wells and cracks in floors, walls and the foundation.
  • Slope ground away from the foundation to allow rainwater to flow away from the home.
  • Direct downspouts from eaves troughs away from the foundation (minimum of 1.2 metres) or to a rain barrel(s).
  • Disconnect downspouts from the sewer system or foundation drains.
  • Ensure foundation drains direct water to the storm sewer or sump pump. Foundation drains should not be connected to the sanitary sewer.
  • Ensure the sump pump is connected to the storm sewer or discharges to the ground at least 1.2 metres from the foundation.
  • Install protective plumbing devices, such as backwater valves which protect against surcharging in City sewers. The City’s Residential Protective Plumbing Program offer rebates to qualified homeowners.
  • Maintain existing protective plumbing devices according to the manufacturer’s instructions. A protective plumbing device should be maintained periodically or before a forecasted heavy rainfall to ensure it is free of debris, functioning properly and that cleanout caps and access covers are firmly secured. For more tips on backwater valve maintenance, refer to a video on Backwater Valve Maintenance(link is external) from the Institute for Catastrophic Loss Reduction.

For more tips on preventing basement flooding, refer to the Handbook for Reducing Basement Flooding from the Institute for Catastrophic Loss Reduction.

Causes of sewer backups and flooding

Backups and flooding can occur as a result of:

Blockage of the lateral

If the lateral from your home becomes blocked, sewage from inside your home may back up into the basement. The blockage may be due to:

  • Accumulation of grease, paper, kitchen waste or other foreign objects
  • Presence of tree roots (private or City-owned trees)
  • Collapse, misalignment or other structural defects of the lateral

Surcharging of the City’s sewer main

If the sewer main, generally located under the street, is blocked or damaged, sewage may enter your home due to increased water level or surcharging in the City’s sewer system.

Spring runoff

Melting snow and ice can leak through cracks or joints in your basement walls or floor.

River flooding

River flooding sometimes occurs in some areas of the city.

To find out if you live in Ottawa's 1-in-100 year flood plain, consult the City's interactive map.

Responsibility for sewer laterals

  • The City is responsible for the portion of the sanitary and storm sewer laterals from the property line to the street.
  • The homeowner is responsible for the portion of the sanitary and storm sewer laterals from the property line to the home.
  • There may also be shared responsibility if a lateral requiring repair or replacement crosses the property line.

Residential Protective Plumbing Program

The Residential Protective Plumbing Program provides financial assistance to qualified City of Ottawa property owners for the installation of protective plumbing devices, such as sump pumps and storm and sanitary backwater valves to prevent water and sewage from flooding homes as a result of increased water level (surcharging) in the City’s sewer system.

For more information, visit the Sewer backups and flooding page.


The City is prepared to provide sand and sandbags if necessary. Sand and sandbags have been deployed to various locations throughout the City, additional locations were added today as a precaution. If residents require sand and sandbags, they can collect material at any of the following locations:


  • 29 Hurdman Road
  • 1683 Woodward Drive
  • Jamieson Street at the Ottawa River


  • 2264 Colonial Road (Navan)


  • 2941 March Road
  • 4127 John Shaw
  • 2121 Huntley Road
  • 1655 Maple Grove Road


  • 2145 Roger Stevens Drive
  • 4244 Rideau Valley Drive

How to make a sandbag wall

Descriptive video