The four home-insurance gaps that cost the most

Why "I have home insurance" isn't the whole story

Home policies cover a lot — fire, wind, theft, most water damage, liability. But the losses that most often blindside owners are the ones sitting in the exclusions. Four gaps account for the majority of nasty surprises, and each is fixable cheaply if you know to ask.

Gap 1 — Overland flood

Water entering your home from overflowing rivers, lakes, or heavy surface runoff is excluded by default and sold as a separate overland water endorsement. With climate-driven flooding rising across Canada, any address with meaningful water exposure should price it. Note the distinction: "overland flood" (surface water) is different from "sewer backup" (below), and you may need both.

Gap 2 — Sewer backup

Water backing up through your drains and sewer is optional coverage, and where it's included it's often capped low. The math is stark:

The endorsement is cheap; the cap is the trap. If you have a finished basement, raise the cap to match what it would cost to rebuild it.

Gap 3 — Earthquake

Earthquake is excluded by default everywhere and sold as an endorsement. It matters most in seismically active regions — coastal British Columbia and the St. Lawrence and Ottawa Valley corridor in Quebec. Earthquake endorsements carry their own (often percentage-based) deductible, so price the coverage and the deductible together.

Gap 4 — Rebuild cost vs market value

Insurance should pay what it costs to rebuild your home, which can be very different from its market value. In hot markets, market value includes land you can't lose to a fire; in others, construction costs exceed the purchase price. If your dwelling limit simply tracks what you paid, you may be badly under-insured — or paying to insure land. Ask your insurer for a rebuild-cost estimate and consider guaranteed replacement cost, which commits the insurer to rebuild even if it exceeds the policy limit.

Bonus traps

• Home business / Airbnb — running a business or short-term rental from home can void parts of a standard homeowner policy. You need an endorsement or a commercial/host policy.
• Older wiring, plumbing, or roof — can trigger higher premiums, refusals, or actual-cash-value (depreciated) settlements instead of full replacement.
• Vacancy — a home left empty beyond the policy's limit (often 30 days) can lose coverage for burst pipes and more.
• Contents sub-limits — jewellery, bikes, and electronics often have low per-category caps; schedule high-value items separately.

Your gap-check checklist

1. Do you have overland flood — and does your address need it?
2. Is sewer backup included, and is the cap high enough for a finished basement?
3. Do you need earthquake coverage for your region?
4. Is your dwelling limit based on rebuild cost, not purchase price? Is guaranteed replacement cost available?
5. Any home business or short-term rental activity that needs an endorsement?
6. Model your deductible choice with the Deductible Optimizer.