When a Neighbour's Regrading Flooded a Sarnia Basement

The situation

Yusuf, a software developer, and Abdi, a pharmacist, bought a bungalow in Sarnia with a finished basement that doubled as a home office and a playroom. For the first two years, the basement stayed dry through every storm. Then their next-door neighbour, Margaret, hired a contractor to repave her driveway and regrade her backyard, building up the soil along the shared property line to fix a low spot near her own foundation.

What Margaret's contractor did not account for was where that water would go once it left her yard. The regrading tilted the slope so that runoff that used to spread across her lawn and soak in now funnelled along the property line, pooling against Yusuf and Abdi's foundation wall every time it rained. The first sign was a musty smell in the basement office. Then a hairline crack appeared near the floor. They mentioned it to Margaret, who was polite but skeptical that her landscaping had anything to do with it, and the conversation went nowhere.

What the evidence showed

For close to a year and a half, Yusuf and Abdi tried to resolve things informally — raising it with Margaret again after heavier storms, patching the crack themselves, running a dehumidifier. They did not take photographs on a consistent schedule, did not get an engineer involved, and did not put anything in writing. By the time they came to Treadstone Law, the basement had visible efflorescence (the white mineral staining left by water moving through concrete), a wider foundation crack, and a mold smell that would not go away no matter how often they ran the dehumidifier.

Our team's first move was to get a geotechnical engineer onto the property before doing anything else. The engineer's report was decisive: surface grading on Margaret's property had been altered to direct water toward the shared property line, and the pattern of saturation around Yusuf and Abdi's foundation was consistent with sustained runoff rather than groundwater or a plumbing issue. That report gave the claim a technical backbone — but it also surfaced a problem. The engineer's timeline, cross-referenced against the couple's own recollection, showed that the earliest and worst damage — the original hairline crack and the first two seasons of water intrusion — had been discovered roughly three years before Yusuf and Abdi sought legal advice.

Under the Limitations Act, 2002, most civil claims in Ontario must be started within two years of the date the person knew, or ought reasonably to have known, that they had a claim worth pursuing. Discovering a crack and a bad smell, and connecting it to a neighbour's landscaping, can be enough to start that clock running — even if the homeowner does nothing about it for a while. Because Yusuf and Abdi had first noticed the problem and suspected the regrading was the cause well outside that two-year window, the earliest and largest portion of the damage — work that would have cost roughly $190,000 to repair — was no longer legally recoverable. Only the damage that had occurred or been discovered within the two years before the claim was filed remained available to pursue.

What we did

1. Retained an engineer immediately, before drafting anything. A demand letter with no technical support invites a neighbour to dismiss it, the way Margaret had dismissed the earlier hallway conversations. The engineering report gave every later step a factual foundation that could survive scrutiny.
2. Ran the limitation period analysis honestly, before building the claim's dollar figure. Rather than pursuing the full repair estimate and hoping the timing issue would not come up, we identified which portion of the roughly $460,000 in total damage — foundation stabilization, waterproofing and mold remediation, temporary housing during repairs, and drainage regrading on their own lot — fell inside the recoverable window. That left about $270,000 in damage that could realistically be pursued, and we built the case around that figure rather than a number likely to be challenged and reduced by a judge.
3. Sent a formal demand to Margaret, supported by the engineering report and repair estimates. This gave her, and the contractor she had hired, a clear opportunity to respond before litigation started — and a clear record that they had been put on notice.
4. Filed a claim in the Superior Court for nuisance and negligence when the demand did not produce a resolution, naming Margaret as the primary defendant. The claim focused specifically on the regrading work and its documented effect on drainage, not on the general state of the relationship between the two properties.
5. Prepared for the contributory negligence argument that Margaret's lawyer was likely to raise — and did. Her engineer pointed out that Yusuf and Abdi's own downspouts discharged close to the same corner of the foundation, meaning some of the saturation could not be attributed to the regrading alone. We did not contest that this was a fair technical point; instead, we used it to calibrate a realistic settlement range rather than pushing for full recovery of the pursued amount at trial.
6. Negotiated a settlement through mediation rather than proceeding to trial, weighing the cost and uncertainty of a contested hearing against a resolution that reflected both the strength of the engineering evidence and the shared causation issue.

The outcome

Margaret agreed to a settlement of roughly $165,000, plus a change to her property's drainage to redirect future runoff away from the shared line. That figure reflected about 61 percent of the $270,000 in damage that remained legally recoverable — a discount that accounted for the couple's own downspouts contributing to part of the saturation, and for the practical reality that a trial carried real risk on both sides.

It was not the number Yusuf and Abdi had hoped for when they first called. The roughly $190,000 tied to the earliest and worst damage was gone, not because the engineering evidence was weak, but because too much time had passed between noticing the problem and getting legal advice about it. That is a hard outcome to sit with, and our team was direct with them about it from the first meeting: the limitation period had already done its damage before the file reached us. What the engagement did accomplish was containment — turning an informal, undocumented dispute that was on track to recover nothing into a settlement that covered the repairs still within reach, funded by the party who caused them, without the cost and delay of a trial that could have gone worse.

The basement was repaired within the year, with new exterior waterproofing and a corrected grade along the property line on both sides. Yusuf and Abdi still speak with Margaret occasionally at the mailbox. It is not the friendship it once was, but the drainage problem is fixed, and neither side is left guessing about who paid for what.

What you can learn from this