Basement Waterproofing Cost in Ottawa

Interior basement waterproofing in Ottawa costs $65 to $150 per linear foot, the median of three Ottawa companies' prices checked 21 October 2026. Two companies publish exterior excavation at $90 to $320 and $100 to $300 a foot. One crack injected costs $400 to $800 or $400 to $900. The cause of the leak decides which you need.

What Ottawa companies publish, side by side

Three companies publish an interior price per foot and two publish an exterior one, so exterior work is shown as two named figures rather than as an Ottawa range. Each price below is the company's own, with the scope it states. Summit Drain & Plumbing is listed in this directory; Aquatech and Ottawa Dry Basement Pros are not.

How the interior range is worked out: the median of the three low ends ($40, $65, $90) is $65, and the median of the three high ends ($150, $150, $160) is $150. Read Aquatech's service card instead of its table and the range becomes $69 to $160. The full spread a homeowner may hear runs from $40 to $190 a foot.

Whole-job prices

Summit puts a whole interior weeping tile job at $4,000 to $17,000 and an exterior job on an existing home at $10,000 to $35,000. Ottawa Dry Basement Pros puts a typical Ottawa basement's interior system at $8,000 to $15,000, depending on size, finishing and whether a sump pit is added, and an exterior membrane at about $15,000 to $30,000 or more.

Foundation crack repair cost in Ottawa

Two companies price one injected crack on its own: Aquatech at $400 to $800 for epoxy, and Ottawa Dry Basement Pros at $400 to $900, which it says is typically one visit with no excavation. Renco Home Improvements, on Checkers Road, prices the whole repair instead, in ranges:

• Non-structural crack repair, $950 to $2,650. Usually an epoxy injection; the price depends on how many cracks there are and how deep or large.
• Structural crack repair, $1,200 to $4,000. Epoxy or carbon fibre staples, for cracks Renco describes as often wider than a quarter inch and horizontal.
• Exterior excavation crack repair, $5,000 and up.

Renco's figure prices a repair job that may cover several cracks, so it sits apart from the per-crack figures and stays out of any range.

Sump pumps and window wells

Summit lists a sump pump at $1,500 to $2,500 or more. Aquatech lists one at $1,500 to $3,500 with the liner, check valve and discharge plumbing, and Ottawa Dry Basement Pros puts a pump with battery backup at $1,200 to $3,000. Aquatech prices a window well at $500 to $1,200 each, dug to the footing with drainage stone.

Check what the City pays before anyone quotes a pump or valve. Its protective plumbing program rebates up to $1,000 for an indoor sanitary backwater valve and up to $3,000 for a sump pump with battery backup in a newly built pit, on homes old enough to qualify, with a building permit pulled first. Replacing a device you already have earns nothing.

Why your basement leaks decides what you pay

The City of Ottawa's page on the causes of basement flooding separates water coming through the foundation from water coming up the sewer, and each points at a different job. Match what you see before you compare prices:

• Water at one crack, after rain or the spring melt. The City says melt and heavy rain can leak through cracks or joints in basement walls or floors. The fix is usually the crack itself, priced per crack.
• Seepage along the joint where the floor meets the wall. That is ground water under pressure. Ottawa Dry Basement Pros names this case for an interior weeping tile to a sump pit, priced per foot.
• Water at one wall, under a downspout or where the ground falls toward the house. Fix the surface first, as the downspout section below sets out. It costs least, and it is on the City's own prevention list.
• Water at a basement window. Overland flooding, in the City's words, seeps in through windows, doors and cracks. Seal or rebuild the window well; Summit suggests a cover to keep water and debris out.
• Water or sewage coming up a floor drain. This one is a sewer problem. The City says a blocked or surcharged sewer main, or a blocked lateral, backs up into a home without a working backwater valve. That valve is a plumber's job, and the City rebates it.
• Damp walls and a musty smell, but no water. Often condensation. Summit suggests a dehumidifier and insulated cold-water pipes. Damp proofing an existing basement needs no City permit.

In an older house, find out where the foundation drain goes

The City says that in some older homes the foundation drains connect to the sanitary or combined sewer, or there are none, and that there the flooding risk is generally from the sanitary or combined sewer. Newer infill may be connected differently. In that kind of house a backwater valve can matter more than any membrane, so have a plumber camera the lateral before a waterproofing crew quotes.

Our guide to what Ottawa plumbers charge lists published prices for a drain camera. Water coming in right now is reported to the City through its basement flooding page, which says requests are typically actioned within three hours to decide whether a site visit is needed. If the problem is the City's sewer main, the City fixes it.

Ottawa's marine clay, and cracks that come back

The City of Ottawa calls it sensitive marine clay, and its 2017 tree-planting guideline uses the term interchangeably with Champlain Sea clay; local companies call it Leda clay. The City's rules for these soils began with a 2005 report on City trees identified as a significant contributing factor for foundation damage.

The guideline draws its line at how much the clay changes volume. Clay with a modified plasticity index above 40 per cent is classed as having a high potential for soil volume change, and in new subdivisions on these soils the foundation walls are to be reinforced with at least two upper and two lower 15M bars.

What that means for a quote: an injection seals a crack, not the movement behind it. A crack that reopens, or a horizontal one, is a structural question. Summit tells readers to call a professional for horizontal cracks, Renco prices structural repair separately, and the City's Building Code Services flood FAQ says to have a professional engineer assess suspected structural damage.

What the City pays: the Residential Protective Plumbing program

The City's Residential Protective Plumbing program rebates the lesser of its maximum or the cost of the work. These are its maximums, read 21 October 2026 from a page dated 4 September 2026:

Five conditions decide whether you get it:

1. The property is a residential unit in the City of Ottawa.
2. It was built before 1 January 2004 for a storm backwater valve, or before 1 January 2012 for a sanitary backwater valve.
3. The device was not installed by the City.
4. A building permit comes first, and the work is finished and the application in within 18 months of the permit's issue date. That window was 12 months until 1 July 2026.
5. The device is new. Rebates are not available for maintenance, repair or replacement of existing protective plumbing devices.

The program pays for devices, not for weeping tile, membranes or crack injection. An exterior job earns nothing from it unless a new pump or valve is in the scope. Ask for those lines to be itemized, because the application needs a paid, itemized invoice.

Where the water may go: downspouts, sump discharge and the sewer

The City's basement flooding prevention list, dated 1 October 2025, gives the distances:

• Redirect downspouts to permeable areas 3 metres from the foundation.
• Disconnect downspouts from the sewer system or the foundation drains, and cap the pipe coming out of the ground.
• Connect the sump pump to the storm sewer, or discharge it to the ground at least 1.2 metres from the foundation.
• Send foundation drains to the storm sewer or a sump pump, never the sanitary sewer.
• Slope the ground away from the house, and clear snow back from the foundation.

The sanitary rule is also in the City's by-laws. Section 5 of the Sewer Use By-law, No. 2025-94, says no person shall discharge stormwater, water from the drainage of roofs or land, or uncontaminated water to a sanitary or combined sewer outside the cases it lists, one of which is a combined sewer connection that existed before 24 October 1984.

The City describes the sanitary lateral as the pipe carrying wastewater from toilets, washing machines, showers and sinks. So a sump pump emptied into a laundry tub sends ground water down the sanitary sewer, which is the discharge the by-law forbids.

Moving downspouts to a rain garden or soak-away pit may qualify for Rain Ready Ottawa in priority areas. Its rebates are not retroactive: the project has to be approved before construction, and the program needs a home assessment, its online courses, or work by a certified Fusion Landscape professional. Downspouts drain only when the troughs feeding them are clear; our gutter cleaning cost guide covers the autumn timing.

Does basement waterproofing need a building permit in Ottawa?

Part of it does not. "Damp proofing of existing basements" is on the City's list of projects that need no building permit, and the work must still meet the Ontario Building Code. Designated heritage buildings and those in a Heritage District Overlay get no exemptions. The list does not mention weeping tile, excavation or membranes, so ask whether a permit is being pulled.

• A sump pit, a sump pump or a backwater valve needs a permit. The City's July 2026 advisory says the application needs floor plans with dimensions, the location, type, make and model of each device, and a completed Schedule 1 for the designer.
• Structural repair needs one. The City's permit FAQ requires a permit for installation, erection, extension or material alteration or repair. Its flood FAQ adds soil eroding near the foundation so that supports settle or the structure sags or leans.
• Digging needs a locate. Ontario Dig Authority, on the site Ontario One Call used, says a locate is free and the law, and completes one for a single address within 5 business days. Wait for every utility to respond before digging.

Finishing the basement afterwards is a different permit question, answered in whether you need a permit to finish a basement in Ottawa.

How each method is done, inside or outside

Interior. Summit describes a perforated pipe laid in the floor around the inner edge of the basement, carrying water to a sump pit, with the pump sending it out through the wall. Aquatech notes it skips excavation, and Ottawa Dry Basement Pros calls it less disruptive than exterior work and suited to a basement you plan to finish.

Exterior. The crew digs beside the foundation to the footing, seals the wall with a membrane, lays new weeping tile and backfills. Ottawa Dry Basement Pros calls it most often the right call for older stone or rubble foundations and long-standing leaks. It keeps water off the wall itself, and it is the dearest job on every price list here.

Timing. Aquatech says jobs are usually scheduled 4 to 6 weeks after you accept, and the start depends on the weather. If the job includes clearing a blocked sewer, Ontario Dig Authority asks you to confirm first that no natural gas line passes through the sewer pipe, because clearing it with mechanical equipment could damage one.

After an Ottawa basement flood: pump it out slowly

The City's Building Code Services warns that pumping a flooded basement too fast can crack the foundation, because saturated soil outside pushes on the walls once the water inside is gone. Its schedule:

1. Start pumping when floodwater no longer covers the ground outside.
2. Pump out one foot (300 mm), mark the level and wait 24 hours.
3. If the water rises above the mark, stop and wait for it to settle.
4. If it holds, pump another foot and wait 24 hours again.
5. Once the level has held for 48 hours, pump two to three feet every 24 hours.
6. Stop and call a qualified professional at any sign of cracks or movement.

Removing drywall so the insulation can dry needs no permit, the same FAQ says; replacing insulation with a different material, such as batts with spray foam, does. Call your insurer as soon as you can, as the City advises. Soaked carpet, drywall and boxes have to leave the house, and junk removal companies in Ottawa haul that kind of load.

How to compare two waterproofing quotes

Ask each company the same six questions, and get the answers in writing:

1. What is causing the water, and which line of this quote fixes that cause?
2. How many linear feet, and on which walls?
3. Is the sump pump, its battery backup and the discharge line in the price, and does it discharge to the storm sewer or to the ground at least 1.2 metres out?
4. Who pulls the permit for a pit, pump or valve, and will the paperwork support the City rebate?
5. For exterior work, who requests the locate, and when?
6. What does the written warranty cover, for how long, and does it transfer?

The directory's basement waterproofing page lists Ottawa companies with their Google rating, the review count behind it and the date it was checked. A backwater valve goes to plumbers in Ottawa. If a dry basement is the first step toward a finished one, the basement renovation cost guide and the basement finishing companies take it from there.