ONTARIO HOME INTEL · MUNICIPAL GUIDE
St. Marys, Ontario Property Guide
A practical 2026 guide to property taxes, zoning, building permits, accessory apartments and buyer due diligence in St. Marys.
2026 Property Taxes in St. Marys
The Town publishes a 2026 property-tax-rate schedule by tax class. Property taxes are calculated by applying the applicable municipal and education rates to MPAC assessment. Buyers should confirm the actual annual taxes from the latest tax bill and, where appropriate, a tax certificate rather than relying only on a listing figure.
Zoning and Planning
St. Marys administers its own Official Plan and Zoning By-law. The zoning by-law regulates permitted uses, building location, setbacks, lot coverage, parking and other site standards. The Town’s zoning materials are consolidated through June 2024, so owners considering development should also check for later amendments and active planning applications.
Building Permits
The Building Department issues permits and conducts inspections for new construction, renovations and other work. Building permits may be required for structural renovations, additions, plumbing work, accessory apartments, decks, accessory structures and changes of use. Starting work without a required permit can create delays, added fees and resale problems.
Accessory Apartments and Additional Units
St. Marys permits accessory apartments subject to zoning and building requirements. The Town’s zoning framework has historically allowed one accessory apartment either within qualifying detached, semi-detached or row/townhouse dwellings or, where the zoning standards are met, in an accessory building. Because provincial housing legislation and local zoning continue to evolve, owners should confirm the current number and configuration of units permitted on the specific property before proceeding.
A building permit is required for a new accessory apartment. The Town also offers a Community Improvement Plan accessory-dwelling-unit grant that can cover 50% of eligible costs up to $5,000 per unit, to a maximum of $10,000, subject to current program rules and approval.
2026 Development Charges
As of January 1, 2026, St. Marys lists development charges of $14,308 for a single or semi-detached dwelling, $11,491 for other multiples, $9,165 for apartments with two or more bedrooms and $6,685 for bachelor or one-bedroom apartments. Exemptions or different treatment may apply to qualifying additional residential units.
Buyer and Homeowner Due-Diligence Checklist
- Confirm zoning and permitted uses for the property.
- Review the latest property-tax bill and tax class.
- Ask for permits and final inspections for renovations and accessory apartments.
- Check whether a proposed secondary unit meets current zoning, servicing and parking rules.
- Confirm heritage restrictions where applicable.
- Review easements, rights-of-way, drainage and lot boundaries.
- Check whether development charges or municipal fees apply to a planned project.
Official St. Marys Resources
St. Marys Property FAQ
Do I need a permit for an accessory apartment?
Yes. Creating a new accessory apartment requires a building permit and must comply with current zoning and Building Code requirements.
Does St. Marys offer grants for accessory units?
The Town’s Community Improvement Plan includes an accessory dwelling unit grant, subject to eligibility, available funding and current program rules.
Should buyers verify old renovations?
Yes. Ask for permit history and final inspection records where additions, finished basements or secondary units are material to the purchase.
For regional context, see the Perth County Property Guide. Explore more Ontario municipality guides, zoning and permit resources and property tax tools.
General information only: Verify current property-specific zoning, permits, taxes and program eligibility directly with the Town of St. Marys before acting.