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Serving the Municipality of Trent Hills (Northumberland County)
Modular Homes & Garden Suites in Trent Hills, Ontario
Factory-direct modular homes and backyard suites for the Municipality of Trent Hills — Campbellford, Hastings, Warkworth and the Percy ward, along the Trent River in Northumberland County. Zoning By-law 2010-105 (§5.27) permits up to two additional residential units per home as-of-right, and a detached backyard unit is expressly allowed. There's no fixed size cap — lot coverage, yards, and height set your envelope. Here's what the by-law allows, what it costs, and the rules that apply.
What you can build in Trent Hills
Full modular homes — from $175,696. 29 models from 560 to 1,405 sq ft, 1–3 bedrooms — factory-built to the Ontario Building Code and set on a permanent foundation (a real, permanent house, not a “trailer”).
Backyard suites (ADUs) — from $96,244. 7 compact models built for garden-suite and in-law-suite use, sized to fit what Trent Hills's by-law allows.
All homes are CSA-certified (A277 modular / Z240MH manufactured), finished in the factory, and delivered ready for foundation and hook-up. What's the difference between modular, manufactured, and mobile? →
Find your backyard suite — 3 quick questions
We'll narrow the models that fit a typical Trent Hills backyard allowance to the ones that fit your life. No email needed.
1 · Who's it for?
2 · What layout?
3 · What size feels right? (Trent Hills lots typically allow up to ~700 sq ft)
Trent Hills sets no fixed m² cap on a detached suite — all accessory buildings together may cover up to 15% of your lot (§5.1 d), so a typical 600 m² (≈6,460 sq ft) town lot allows up to about 90 m² (≈968 sq ft) of accessory footprint, shared with any existing shed or garage; rural lots allow more. Enter your address for the specifics. Your exact lot may allow more or less — get the real number for your address in seconds.
Check your exact Trent Hills address →Can you put a garden suite (ADU) in your Trent Hills backyard?
Often, yes — Trent Hills permits a detached Additional Residential Unit on most serviced residential lots. The specifics, from Municipality of Trent Hills Comprehensive Zoning By-law 2010-105, §5.27 — Additional Residential Unit (March 2026 office consolidation):
| Max size | No fixed m² cap. The envelope is set by lot coverage: all accessory buildings together may cover up to 15% of the lot (§5.1 d), and on an urban R1/R2/R3 lot all structures together up to 45% (§5.27 l). On a typical 600 m² (≈6,460 sq ft) town lot that means up to about 90 m² (≈968 sq ft) of accessory footprint — shared with any existing shed or garage. |
|---|---|
| Where it goes | Inside the house OR in a separate building ancillary to a single-detached, semi-detached or rowhouse home (§5.27). Up to 2 additional units per primary home; on an urban R1 lot the total number of units is capped at 4 (§7.1 i). |
| Height & setbacks | A detached suite can’t be taller than your main home (§5.27 n). It must sit at least 1.5 m (≈5 ft) from the house (§5.1 c) and 1.2 m (≈4 ft) from the side and rear lot lines (§5.1 i). |
| Parking | 1 space per unit — a tandem space in your existing driveway qualifies, and the suite can’t have a driveway of its own (§5.27 d–e). |
| Servicing | Municipal services in the urban areas; on a rural well+septic lot the unit is permitted for a single-detached or semi-detached home subject to your water supply and septic system being able to serve the extra unit (§5.27 c, §5.28) — confirm septic capacity before you design. |
| Conservation | Three authorities share Trent Hills: Lower Trent Conservation (most of the municipality, incl. Campbellford, Warkworth and Percy), Crowe Valley (northeast) and Otonabee (northwest fringe). No ARU is permitted in an area identified as subject to flooding or in the Environmental Protection (EP) Zone (§5.27 f). |
Getting your building permit in Trent Hills
An eligible lot still needs a building permit before anything is delivered. Here's how Trent Hills's process actually works — verified against the Trent Hills building department's own pages.
How do you apply for an ADU building permit in Trent Hills?
Through Trent Hills Permit Portal (Citywide) — Municipality of Trent Hills Building Services, 66 Front St S, Campbellford, 705-653-1900 (application portal ↗). Trent Hills takes building-permit applications online through its Citywide permit portal, or in person at Building Services in Campbellford. Before applying, check the property's zoning with a Development Inquiry Form on trenthills.ca. Confirm the current process and fees on the Municipality's Building Permits page (705-653-1900 / info@trenthills.ca). Trent Hills's building-permit page ↗
- Confirm zoning — up to two additional residential units per primary home are as-of-right under Zoning By-law 2010-105 §5.27, including a detached backyard unit ancillary to a single-detached, semi-detached or rowhouse home. No fixed m² cap: all accessory buildings together may cover up to 15% of the lot (§5.1 d), the suite can't be taller than the main home, and it needs 1.5 m from the house and 1.2 m side/rear setbacks. Check zoning via the Development Inquiry Form on trenthills.ca.
- Check with your conservation authority — three share Trent Hills (Lower Trent Conservation for most of the municipality incl. Campbellford, Warkworth and Percy; Crowe Valley in the northeast; Otonabee on the northwest fringe). An ARU is not permitted in an area identified as subject to flooding or in the Environmental Protection (EP) Zone (§5.27 f) — near the Trent River or a watercourse, get the authority's confirmation first.
- Servicing: on an urban serviced lot, a water/sewer application accompanies the permit. On a rural lot, the water supply and septic system must be able to serve the extra unit (§5.27 c, §5.28) — a sewage-system permit application goes to the Trent Hills Building Department (new system $875 under the 2026 fee schedule).
- Confirm the property entrance is registered and up to municipal standards — an Entrance Permit may be required (municipal roads via Trent Hills; county roads via Northumberland County).
- Retain a qualified BCIN designer for the Ontario Building Code construction drawings (an owner designing their own home may claim the homeowner exemption on Schedule 1).
- Submit the application through the Citywide portal or in person with the drawings and fees; respond to any plans-examination comments.
- Book building inspections through construction — municipal building inspections via Building Services, a separate ESA electrical inspection, and plumbing inspections through the County of Northumberland — to occupancy.
What does a Trent Hills ADU permit application need?
- Application for a Permit to Construct or Demolish + Schedule 1 Designer Information (BCIN, or the homeowner exemption)
- Site plan showing property lines, setbacks from all lot lines and structures, and the proposed construction (a survey works; example on trenthills.ca)
- One set of building plans to scale, minimum 11" × 17" — floor plans, elevations, and cross-sections
- Energy Efficiency Design Summary (EEDS) and HVAC documents (HRAI heat loss/gain and ventilation design)
- Sewage System Permit application (rural well+septic lot) or water/sewer application (urban serviced lot)
- Letter of Authorization from the property owner if the applicant isn't the owner
How much does an ADU building permit cost in Trent Hills?
Building-permit fees follow Schedule H of the Fees and Charges By-law 2025-082 (passed December 9, 2025, in force January 1, 2026): a flat administration fee of $400 for a residential permit plus $0.95 per sq ft of finished area — so a 700 sq ft detached suite works out to roughly $1,065. Confirm with Building Services how a detached ARU is classified (the accessory-building rates — $200 admin + $0.75/sq ft — are lower) and whether the refundable $5,000 residential new-build deposit applies. A new septic system adds $875. All figures are estimates — confirm with Building Services (705-653-1900).
| Building permit — administration | $400 flat for a residential permit ($200 for accessory buildings) — Schedule H, Fees and Charges By-law 2025-082 (2026) |
|---|---|
| Building permit — per-area fee | $0.95 per sq ft finished area for dwellings ($0.40 unfinished; $0.75 for accessory structures) — ≈ $665 on a 700 sq ft suite |
| Refundable residential new-build deposit | $5,000, refunded when all permits close at final inspection — confirm whether it applies to a detached ARU |
| Septic (sewage-system) permit — rural lot | $875 for a new system / $475 for a repair, issued by the Trent Hills Building Department (2026) |
| Development charges | EXEMPT — Trent Hills expressly lists additional residential units among its DC exemptions (DC By-laws 2024-023 to 2024-026, as amended) |
Trent Hills expressly lists additional residential units among its development-charge exemptions (DC By-laws 2024-023 to 2024-026, as amended; rates indexed each February 20). Confirm the exemption for your project with the Municipality when the permit is issued.
How long does an ADU building permit take in Trent Hills?
Ontario's Building Code requires a decision on a complete house-class application within 10 business days. A house-class building permit is reviewed within the legislated 10 business days once a complete application is submitted. A conservation-authority approval — likely near the Trent River, Crowe River, or a mapped flood area — comes first and can add time, as can the septic-capacity confirmation on a rural lot.
Registration: Trent Hills does not publish a separate ADU registration or licensing fee — the building permit is the approval. Confirm with Building Services.
Worth knowing before you apply
- The fee schedule includes a refundable $5,000 deposit on residential new builds, returned when the final inspection closes all permits — budget for the float and confirm with Building Services whether it applies to a detached ARU.
- Three conservation authorities share Trent Hills (Lower Trent, Crowe Valley, Otonabee) — an ARU is not permitted in a mapped flood area or the EP Zone, so near the Trent River get the authority's sign-off before you design.
- Septic (sewage-system) permits are issued by the Trent Hills Building Department itself ($875 new), but plumbing permits and inspections run through the County of Northumberland — two different offices.
- The big number is a saving: additional residential units are expressly exempt from Trent Hills development charges (DC By-laws 2024-023 to 2024-026).
- Check the entrance: if the property's entrance isn't registered and up to municipal standards, an Entrance Permit is required before the building permit.
Fees and timelines are estimates from Trent Hills's published schedules, verified August 26, 2026. Rates and processes change — always confirm current requirements with the building department before you apply.
Grants & financing in Trent Hills
Development-charge exemption for additional units — Trent Hills expressly lists additional residential units among its development-charge exemptions (DC By-laws 2024-023 to 2024-026, as amended) — confirm the current treatment with the Municipality for your project.
See every program → Ontario ADU Grants Directory
A modular or prefab home on a permanent foundation is financed like any house. CMHC Prefab Plus allows an insured mortgage with as little as 5% down on the first $500,000, with construction funds released in stages. How modular home financing works →
Thinking of the suite as a rental? Run the numbers →
Trent Hills modular homes — FAQ
Can you build a garden suite / ADU in Trent Hills?
Yes — Zoning By-law 2010-105 (§5.27) permits up to two additional residential units per primary home as-of-right, and one may be in a separate backyard building ancillary to a single-detached, semi-detached or rowhouse home. It needs a building permit and must meet the Ontario Building Code; it isn’t permitted in a mapped flood area, the EP Zone, on a private road with limited emergency access, or on a lot that already has a garden suite.
How big can a backyard suite be in Trent Hills?
There’s no fixed maximum m². All accessory buildings together may cover up to 15% of your lot (§5.1 d) — about 90 m² (≈968 sq ft) on a typical 600 m² town lot, more on a larger rural lot — and on urban R1/R2/R3 lots all structures are capped at 45% total coverage (§5.27 l). The suite also can’t be taller than your main home. Enter your address for the specifics.
Can you build an ADU on well and septic in Trent Hills?
Yes — on a rural lot the by-law permits the unit for a single-detached or semi-detached home, subject to your water supply and septic system being able to serve the extra unit (§5.27 c, §5.28). The septic-capacity confirmation goes through the approval authority — plan it before you design. Sewage-system permits are issued by the Trent Hills Building Department.
Can you put a modular home in Trent Hills, Ontario?
Yes. On land you own, a modular home on a permanent foundation is legal residential housing under the Ontario Building Code throughout Trent Hills — in Campbellford, Hastings, Warkworth and the rural wards — as the principal dwelling or as an additional residential unit.
How much does a modular home or backyard suite cost in Trent Hills?
Modular home models start at $175,696 and run to about $338,000 for the largest layouts; backyard ADU models start at $96,244. Site work, foundation, delivery, and permits are additional.
Can I get a mortgage on a modular home in Trent Hills?
Yes — on a permanent foundation it is financed as real property, including via CMHC Prefab Plus (5% down on the first $500,000).
Local rules summarized from Municipality of Trent Hills Comprehensive Zoning By-law 2010-105, §5.27 — Additional Residential Unit (March 2026 office consolidation); verified by Modular Homes 400 and reviewed by James Clarke, REALTOR®. Always confirm current requirements with the City of Trent Hills before you build.