The client
A household bought a $312,000 home in Sept-Iles at 10% down, on a lot that happens to straddle the boundary between two adjoining municipalities.
Purchase price
$312,000, Sept-Iles
10% down, insured
Larger municipal tax bill
$185/month
The bill the first lender found
Second municipal tax bill
$95/month
The other municipality's own bill for its portion of the lot -- missed initially
Combined income
$7,300/month
The problem
When a single lot's boundary crosses from one municipality into another, each municipality separately assesses and bills its own portion of the property -- an ordinary consequence of municipal boundaries not always following lot lines, not a defect in the property itself.
What the first review missed
- ▸The property draws two separate municipal tax bills, one from each municipality whose boundary it straddles
- ▸The first lender's file review found the larger $185/month bill and treated it as the property's complete property tax picture
- ▸The second municipality's own $95/month bill for its portion of the lot never made it into the carrying-cost calculation at all
Nobody was hiding anything. The property simply has two landlords for tax purposes, and only one of them had been asked.
The numbers
Correcting the carrying-cost figure to include both bills was the entire fix -- everything else about the file was already right.
| The insured purchase, correctly costed | Amount |
|---|---|
| Base mortgage (90% of purchase price) | $280,800 |
| CMHC premium (3.10% at 90% LTV) | +$8,705 |
| Total insured mortgage | $289,505 |
| GDS at the qualifying rate | Counting one bill | Counting both bills |
|---|---|---|
| Payment at the qualifying rate (7.05%), 25 years | $2,037/mo | $2,037/mo |
| Municipal tax bill(s) | $185/mo | $280/mo |
| Heat (lender estimate) | $120/mo | $120/mo |
| GDS | 32.1% | 33.4% |
Both figures sit well inside CMHC's 39% GDS ceiling -- this was never a marginal file. The point is that 33.4% is the property's real carrying cost, and 32.1% was simply incomplete, consistent with how tightly household debt service ratio data shows these figures are typically reviewed before approval.
The solution
A courtier hypothecaire licensed under Quebec's Act respecting the distribution of financial products and services treated the property's tax picture as something to verify directly, not assume from a single bill.
First, confirmed with both municipalities' own assessment offices that the lot genuinely straddles their shared boundary, and that each was billing its own portion of the property separately.
Second, obtained both current tax bills directly, rather than relying on the one document the file already had on hand.
Third, rebuilt the carrying-cost figure using both bills together before returning the file to underwriting, so the GDS figure the lender actually relied on reflected the property's real cost.
The outcome
The purchase funded insured at 33.4% GDS and 36.7% TDS, with Quebec's welcome tax on the $312,000 purchase coming to $2,806 -- the property's split tax roll has no effect on the transfer duty itself, which is based on the sale price, not the assessment.
Both figures sit comfortably inside CMHC's 39% GDS and 44% TDS maximums; the file was never close to either ceiling, correctly costed or not.
What to take from this file
- 01A lot can straddle a municipal boundary without anything being wrong with the property itself. Municipal boundaries and lot lines don't always align, and each municipality assesses its own portion.
- 02Don't assume one tax bill is the whole picture on a boundary-adjacent property. Confirm directly with the municipality (or municipalities) whether more than one bill exists.
- 03A property's split tax roll is a carrying-cost question, not a title defect. It has no bearing on the transfer tax owed at closing, which is based on the sale price.
- 04A missing bill understates GDS quietly. This file was never at risk of exceeding CMHC's ceiling -- but a thinner file with the same gap could be.
Sources
Every regulatory figure in this file traces to one of these primary sources. Client details and anything that varies by lender are illustrative, as flagged below.
- ▸CMHC — Purchase (Mortgage Loan Insurance) — default-insurance premium schedule by LTV band (25-year amortization).
- ▸CMHC — CMHC Home Start — minimum down payment tiers (5%/10%) and the $1.5M insured price cap.
- ▸OSFI — Minimum qualifying rate for uninsured mortgages — the minimum qualifying rate — greater of contract rate + 2% or 5.25%.
- ▸CMHC — CMHC Reviews Underwriting Criteria — GDS 39% / TDS 44% maximums and the 600 credit-score floor for insured files.
- ▸Provincial/territorial mortgage-broker legislation fetched directly (bclaws.gov.bc.ca, legisquebec.gouv.qc.ca, fcaa.gov.sk.ca, web2.gov.mb.ca, nslegislature.ca, assembly.nl.ca) plus FCNB's own site for NB and CanLII's index for PE — see notes for per-province method — provincial mortgage regulators and licence titles.
- ▸Gouvernement du Québec — Droits sur les mutations immobilières — Quebec's transfer duties ('welcome tax') — 2026 indexed brackets.
Illustrative in this file — lender-specific, not rules:
- ▸5.05% contract rate — rates move daily; not a quote.
- ▸the property's split assessment across two municipalities — this reflects one specific lot's own boundary geography, not a general Quebec rule.
Authority & provenance
How this case file was built
We publish the origin, the verification method and the reviewer for every case file, so you can judge how far to trust it before you rely on it with a client.
Where it comes from
Derived from files handled by Treadstone’s fulfillment desk and from scenarios contributed by partner brokerages. Names, employers, exact amounts and dates are changed so no client or file is identifiable.
Provenance: Composite — a pattern seen repeatedly on fulfilled files, not a single transaction.
What is verified
Every regulatory figure traces to a primary source listed above and was checked against it on the date shown. The arithmetic is recomputed by machine on every rebuild.
Anything that varies by lender is labelled illustrative rather than stated as a rule.
Who reviewed it
Reviewed for Canadian regulatory accuracy before publication, and re-checked whenever a cited rule changes.
Reviewed by: Nicholas Parson, Treadstone Associates — reviews every case file before publication.
This case file is professional reference material for licensed mortgage professionals. It is not advice to a borrower, and it is not a lender commitment. Insurer rules, qualifying rates and provincial taxes change — confirm the current position with the insurer, regulator or lender before you rely on any figure here in a live file.