In short
- The City of Ottawa lists spring runoff and heavy rain as causes of basement leaks through foundation cracks and joints.
- Hydro Ottawa suggests backup power that can run a pump for up to 72 hours and a ground fault outlet for the pump.
- City rule for the outlet: the storm sewer, or open ground 1.2 metres or more away from the foundation wall.
- If water reaches outlets or panels, call Hydro Ottawa at 613-738-0188. The utility waives its connect and disconnect fees for flooding.
- Downspouts should end on permeable ground 3 metres out, the City asks, so roof melt stays out of the pit.
Why spring tests the pit
A sump pump idles for months and then works every few minutes. In Ottawa the heaviest load arrives with the thaw. Snow packed against the foundation melts, the ground below is still frozen in places, and rain on top of the melt sends water toward the lowest point in the house. The City of Ottawa describes this directly: melting snow and ice from spring runoff, or a heavy rainfall, can leak through cracks or joints of a foundation in the basement walls or floor.
Conservation authorities watch the same pattern. In March 2023 the Rideau Valley Conservation Authority warned of flooding if heavy winter snow melts too quickly. Hydro Ottawa’s March 2025 sump pump blog opened with residents bracing for meltwater after an exceptionally snowy season.
Three sources of spring water
The City separates the causes, and each one points to a different device.
Groundwater and meltwater reach the pit through the foundation drains, and the pump handles that water. Overland flow enters through windows, doors and cracks; the City names snowmelt and rainstorms as its two most common triggers. Sewer surcharging pushes sewage through floor drains, and the answer there is a backwater valve, covered on the backwater valve page.
The power-outage gap
Hydro Ottawa points out that submersible and pedestal pumps rely on electricity. It lists battery backup, a water-powered alternative and a generator able to run the pump for up to 72 hours.
A battery backup system sits beside the main pump in the same pit. The choice and the price are covered in the sump pump cost guide. The City of Ottawa rebates battery backup or generator-connected pumps under its protective plumbing program, and the full table is on the sump pump page.
Electrical safety near water
A sump pump is an electrical device in a wet place. Hydro Ottawa advises connecting it to a ground fault circuit interrupter outlet. If flood water reaches outlets, panels or equipment, Hydro Ottawa says to stay out of the basement and call 613-738-0188 to have the electricity turned off. The utility waives its connect and disconnect fees for homes affected by flooding.
A generator hookup is electrical work, and the City asks for an electrical inspection of it under the rebate.
Where the discharge goes
In April the outlet matters as much as the pump. The City wants the pump piped to the storm sewer or released onto ground a minimum of 1.2 metres from the house, with foundation drains running to the storm sewer or the sump and kept off the sanitary line. On a frozen lawn, water released close to the wall soaks straight back to the weeping tile, so ask the plumber where yours ends. The City’s Rain Ready Ottawa program can rebate yard and downspout work, up to $5,000 in its priority areas.
Rivers and low ground
Each spring the City breaks up Rideau River ice to cut flood risk. Hydro Ottawa lists homes near the Rideau and Ottawa Rivers as higher risk, and the City maps the 1-in-100 year flood plain. Local conditions are on the Barrhaven and Orléans pages.
If water is already in
Call 3-1-1 to report the flood. Flood water may contain sewage. Tell your insurer, and keep photos and receipts. The emergency plumber page covers the urgent request.
Who you are dealing with
A pre-thaw check, a battery backup or a new pump is done by an independent Ottawa plumbing company. Ottawa Plumbing Desk forwards what you tell us about last spring, and that company phones, looks at the pit and the power supply, and prices the work on its own terms.
Questions to ask the company
- Will you check the pump before the thaw, and does the visit include the discharge line and the check valve?
- What happens to my pit if the power goes out for a day, and how long does the backup run?
- Does the discharge end in a spot that drains away from the foundation, and where does the water go on a frozen lawn?
- Is my pump big enough for the water this pit collects in April?
- Does a pump alarm make sense in my basement, and what does it add?
Have this ready for the call
- What happened in the last thaw: where water showed up, how high, for how long
- Photos of the pit, the pump and the discharge pipe where it exits the house
- Whether the power has failed in a storm, and whether any backup exists
- The age of the pump and any noise it makes when it starts
- Clear access to the pit and the outlet, with boxes moved off the floor around it
Questions people ask
Why does my basement get wet in March when it did not rain?
The City of Ottawa names melting snow and ice from spring runoff as a cause: meltwater leaks through cracks or joints in foundation walls and floors. It also lists overland flow through windows, doors and cracks. Snowmelt and rainstorms are the two most common causes of overland flooding.
Is a sump pump enough protection in a river flood?
A pump moves groundwater from the foundation drains. It does not stop river water or sewage. The City says river flooding happens in some areas and publishes a 1-in-100 year flood plain map. Hydro Ottawa links the same conservation authority map and lists low-lying areas near the Ottawa and Rideau Rivers as higher risk.
What backup does Hydro Ottawa suggest for a power outage?
Hydro Ottawa says a pump relies on electricity, so a battery backup, a water-powered unit or a generator able to run the pump for up to 72 hours is worth considering. It also mentions a pit cover and a failure alarm.
Should I have the pump looked at before the snow melts?
Hydro Ottawa suggests an annual inspection by a qualified technician, especially before spring thaw, and the City asks owners to maintain protective plumbing devices before forecast heavy rain.
Can ice in the discharge pipe cause a flood?
Hydro Ottawa tells owners to make sure the discharge line is free of obstructions and ice in the cold months. A frozen or blocked line sends the water back into the pit. A plumber can reroute or protect the outlet so it still drains away from the foundation.
What should I do if the basement already has water and the pump is running?
Stay out if water has reached outlets, panels or equipment, and call Hydro Ottawa at 613-738-0188 to have the power turned off. For gas appliances in the water, call Enbridge. Call 3-1-1 to report the flood, and tell your insurer.
