Garden Suites in York Region: Five Towns, Five Rulebooks
Markham, Vaughan, Richmond Hill, Newmarket and Aurora all sit on the same provincial floor: on a serviced urban lot you can have up to three units, and one of them can be in a detached building. After that the towns go their own way, and the differences are big enough to kill a project on one side of a town line and approve it on the other.
At a glance
*Provincial exemption for a qualifying second unit in an ancillary building. School board charges can still apply. Confirm with your town before you budget.
Yes, most York Region house lots on town water and sewer can take one detached unit. Newmarket caps it at 75 m² for one storey or 100 m² for two (or 10% of the lot, whichever is less). Richmond Hill allows up to 80 m² of building coverage and 7.5 m of height. Vaughan needs 4.0 m from the house. Markham is the strictest of the five. No lot on well or septic qualifies in Vaughan or Richmond Hill.
We Don’t Build in York Region. We still know where it goes wrong.
We are a builder based in Tiny Township. We build garden suites in Simcoe County and around Georgian Bay through ICFhome.ca. Outside Simcoe, we sell lot reports, permit packages and builder calls. We do not pour footings in Markham or Aurora.
That is useful to you. We have nothing to gain from telling you a lot works when it doesn’t. We have been building since 1979, and the expensive mistakes look the same in every town: someone buys a kit or signs a contract before anyone checks the zoning, the sewer lateral or the fire path.
What each town calls it
Search for “garden suite” on a York Region town website and you will often get nothing. None of these five uses that word as its main term. Here is the vocabulary you need:
- Markham: “secondary suite” in its homeowner guide, “additional dwelling unit” in the zoning by-law, and “coach house or garden home” when it talks about a detached unit.
- Vaughan: “Additional Residential Unit” in an “Accessory Building” in By-law 082-2025; the website says “secondary suite / ADU”.
- Richmond Hill: “Additional Residential Unit” in an “Accessory Residential Building”.
- Newmarket: “Detached Additional Residential Unit”, shortened to DARU.
- Aurora: “Ancillary Unit” in Registration By-law 6660-24; the building pages still say “second suite”.
Same idea, five names. Use the town’s word when you email the planning desk and you will get a faster answer.
York Region Garden Suite Rules compared
These are the numbers each town publishes for a unit in a detached building. Where a town does not publish a number, we say so instead of guessing. The zoning by-law always wins over this table.
| Town | Max size | Max height | Setbacks / separation | Parking | Servicing |
|---|---|---|---|---|---|
| Markham | Not published in guide — check By-law 2024-19 | Not published — check by-law | Per zone (Part 6.0, By-law 2024-19); entrance 1.2 m from side line | 1 extra space for a coach house or garden home | Mostly municipal; septic lots may need upgrades |
| Vaughan | Not more than the GFA of the main dwelling | Not in ARU section — check by-law | 4.0 m from main building; entrance 1.2 m from side line | 1 per ARU outside protected transit areas | Municipal water and sanitary only |
| Richmond Hill | 80.0 m² building coverage | 2 storeys; 7.5 m to peak; 6.0 m walls | Rear 1.2 m; side 1.2 m; 4.0 m from house; rear yard only | 0 to 3 spaces depending on area | Municipal water and sewer only |
| Newmarket | Lesser of 10% of lot or 75 m² (1 storey) / 100 m² (2 storey) | 5.5 m pitched / 3.5 m flat (1 storey); 6.5 / 5.5 m (2 storey); never above the house | 1.8 m side and rear (1 storey); 2.4 m (2 storey); 3.0 m from house | 1 exterior space per ARU, plus 2 for the house | Municipal, or proven adequate private services |
| Aurora | Not published — check Zoning By-law 6000-17 | Not published — check by-law | Rear or interior side yard; 1.2 m path to street | Must meet applicable law | Not published — check with the Town |
Last checked October 2026 · Sources: Newmarket By-law 2026-10, Richmond Hill By-law 143-24, Vaughan By-law 082-2025, Markham Secondary Suites Guide 2025, Aurora By-law 6660-24
What You Can Build in each town
Markham: the tough one
Markham has the most cautious approach in the region. Council worked through a plan to allow four units per lot under its Housing Accelerator Fund commitments. On March 12, 2026, the mayor used strong mayor powers to revoke it, as Global News reported. So Markham sits at the provincial minimum, not above it.
The provincial minimum still matters. On a serviced urban lot the Planning Act lets you have up to three units, with one allowed in a detached building. What Markham controls is everything around that: setbacks, height and coverage under the new comprehensive Zoning By-law 2024-19.
Markham’s 2025 homeowner guide gives you the parts that trip people up:
- A coach house or garden home needs one additional parking space. Spaces are at least 2.75 m by 5.8 m. Street parking does not count.
- Fire access: a clear 1.2 m path from the street to the unit entrance, no more than 45 m from the fire truck to the entrance, and no more than 90 m total from hydrant to truck to door.
- Each unit needs its own heating system and its own water shut-off. Flood-prone lots need a backwater valve per unit.
- After construction, every suite is registered with Markham Fire and Emergency Services. You need proof of insurance covering two units and an electrical inspection report.
Markham’s guide does not publish a maximum size or height for a detached unit. Ask zoning in writing, at BuildingARUs@markham.ca, before you pay for drawings.
Vaughan: four metres from the house, and town services only
Vaughan’s rules live in By-law 082-2025, in force March 25, 2025. Section 4.1.8 lets you put one ARU in the main house and one in an accessory building. Two clauses decide most Vaughan projects:
- Municipal water and sanitary only. No ARUs on lots with a well or septic, full stop (s. 4.1.8(i)).
- 4.0 m from the house. The accessory building must sit at least 4.0 m from the principal building (s. 4.1.8(ix)). On a shallow lot, that 4 m plus your rear setback is where the plan dies.
The unit cannot be bigger than the main house. You need a separate entrance and a 1.2 m hard-surfaced walkway from the street or driveway. Total lot coverage can go to 45% or the zone maximum, whichever is greater. Outside a Protected Major Transit Station Area, add one parking space per ARU. You also cannot add an ARU to a building with a home occupation or a bed and breakfast in it.
Richmond Hill: the most generous numbers
Richmond Hill’s By-law 143-24 (passed December 11, 2024) allows up to three ARUs on top of the main house, four units total, and up to two of those ARUs in one accessory building. That is a real two-unit backyard building, which most towns do not allow.
- Building coverage up to 80.0 m² (861 sq ft), including any garage in it.
- Up to two storeys: 6.0 m to the top of the walls, 7.5 m to the peak.
- 1.2 m from the side and rear lot lines, 4.0 m from the house, and rear yard only.
- A clear 1.0 m hard-surfaced path with 2.1 m headroom when the entrance is off a side or rear yard.
- At least 50% of the rear yard stays soft landscaping. Lawn, not interlock.
Parking depends on which of four areas you are in, from zero spaces to three. The town also offers a pre-approved detached ARU model, about 6.64 m by 5.47 m (roughly 36 m² or 390 sq ft). You still need a site plan for your own lot and a declaration form with the permit. Accessory buildings over 400 sq ft also need a Site Alteration Permit from Development Engineering, which catches a lot of people off guard.
Newmarket: the clearest rulebook
Newmarket passed By-law 2026-10 on March 30, 2026. It is the most complete detached-unit by-law in the region, and we wish more towns wrote them like this.
- One DARU per lot, two ARUs maximum in total.
- One storey: lesser of 10% of the lot or 75 m² (807 sq ft). Two storeys or above a garage: lesser of 10% or 100 m² (1,076 sq ft).
- Height: 5.5 m pitched / 3.5 m flat for one storey; 6.5 m / 5.5 m for two storeys. Never taller than the house.
- Setbacks: 1.8 m side and rear for one storey, 2.4 m for two storeys. 3.0 m from the house.
- No more than 60 m from the street curb to the unit entrance. A 1.2 m clear path with 2.1 m headroom.
- No rooftop patio. A basement is allowed, with the finished floor no more than 1.2 m above grade.
Watch the 10% rule. On a 500 m² lot, 10% is 50 m², not 75. Small lots get small suites. Parking is one exterior space per ARU on top of two for the house, and the spaces cannot be inside a garage.
Aurora: registration first, numbers in the zoning
Aurora’s Registration By-law 6660-24 (December 10, 2024) allows up to three units per parcel including the main house, with no more than one unit inside the house and one Ancillary Unit outside. The Ancillary Unit has to sit in the rear or interior side yard. Every ARU is registered separately, and you need a 1.2 m path from each entrance to the street, driveway or parking.
One line in that by-law is unusual: the detached unit is defined as “designed to be portable.” Ask the Town how it reads that before you design a frost-wall foundation. Size, height and setbacks sit in Zoning By-law 6000-17, and the Town’s secondary dwelling units page does not publish them. Call Building Services before you draw anything.
How a York Region Permit actually goes
The order is roughly the same in all five towns. The fees are mostly buried in fee by-laws, so here is what is published and what is not.
Confirm zoning in writing
Markham has a Property Details Search, Richmond Hill a Zoning By-law Inquiry Form, Newmarket a Zoning Preliminary Review (the ZPR fee comes off your permit fee later). Get the answer by email. A phone call is not a permit.
Check the conservation authority
Much of York Region drains to TRCA or LSRCA watersheds. Richmond Hill lists TRCA approval as a permit document where the lot is regulated. Find out before you design, not after.
Get stamped drawings
Richmond Hill wants a site plan, floor plans, elevations, sections, heat loss and heat gain, and an energy efficiency summary, all by an architect, engineer or BCIN designer. For a new detached unit, assume every town wants the same.
Apply and pay the permit fee
None of the five publishes a flat garden suite permit fee on its ARU page. It is calculated by floor area in each town’s building fee by-law. Newmarket says a decision comes in 10 to 20 business days and work must start within 6 months.
Build, inspect, get an ESA report
Footings, framing, plumbing, insulation, fire separations and final. Electrical is a separate ESA permit in every town. Book inspections before you cover anything up.
Register the unit
Newmarket: one-time $268.93, plus an “N” plate and a “B” address. Markham registers through Fire and Emergency Services (fee not published). Aurora registers each ARU separately. Skip this and your insurer may have questions you can’t answer.
Last checked October 2026 · Sources: Newmarket ARU page, Richmond Hill ARU page, Markham guide
Development Charges, Grants and pre-approved plans
Development charges. Since Bill 23 (November 28, 2022), Ontario’s Development Charges Act exempts a second unit in an ancillary building where the main house has no more than two units. That covers the usual garden suite. Richmond Hill’s 2025 development charge brochure points to the same Act sections and separately exempts accessory structures up to 100 m². The catch is education development charges from the school boards, which are a separate charge. Ask your building department which charges will be on your permit invoice. Our development charges page explains the exemption in plain English.
Grants. We found no current town grant for a detached unit in any of the five towns in October 2026. If a sales rep tells you about a York Region garden suite grant, ask for the program page on the town’s own website. For federal and provincial money, see our funding directory.
Pre-approved plans. Only Richmond Hill offers a town pre-approved detached model, and it is small. It saves design time, not site work. You still need a site plan, grading, a sewer and water route, and a heat loss for your exact orientation.
| Town | DC on qualifying detached unit | Town incentive | Pre-approved plans | Registration |
|---|---|---|---|---|
| Markham | Provincial exemption — confirm | None found | No | Required, Fire Services (fee not published) |
| Vaughan | Provincial exemption — confirm | None found | No | Check with Building Standards |
| Richmond Hill | Exempt per DC brochure (Act ss. 3.2, 3.3) | None found | Yes, one detached model | Not published |
| Newmarket | Provincial exemption — confirm | None found | No | Required, $268.93 one-time |
| Aurora | Provincial exemption — confirm | None found | No | Required, each ARU (fee not published) |
Last checked October 2026 · Sources: Richmond Hill DC brochure 2025, Newmarket ARU page, Aurora By-law 6660-24
Want the drawings without hiring three firms?
Our permit packages bundle the site plan, grading coordination, forms and the heat loss calculation, with stamped pieces by the right BCIN holder. Send us what you have and we quote a fixed price.
The Pipes Decide more projects than the planners do
Zoning tells you where the building can sit. Servicing tells you whether it can have a toilet. In York Region, these are the four that bite:
- Town water and sewer is not optional in Vaughan or Richmond Hill. Both require the lot to be on municipal services. If you are on a well and septic in rural Vaughan or Richmond Hill, a detached unit is not on the table under these rules.
- Sewer depth. A garden suite at the back of a deep lot may sit lower than the house drain. If gravity won’t carry it, you are buying a pump and a pump chamber. Get the house lateral depth before you place the suite.
- One water service, one meter. Most towns feed the suite off the house service. A 19 mm line feeding two kitchens and two showers will be disappointing. Ask what size service you have.
- Electrical capacity. Markham’s guide says plainly that the house service must be sized for the suite. A 100 amp panel feeding a heat pump suite out back is not going to work. Budget for a service upgrade early.
Newmarket is the only one of the five that allows “demonstrated adequate private servicing.” If that is your situation, the septic design has to come from a qualified designer. We send those to SepticReplacement.ca.
Common Mistakes in York Region
Reading another town’s rules
Your neighbour’s cousin built a 100 m² suite in Newmarket. You live in Aurora. Different by-law, different answer. Check the town line on your tax bill, not your mailing address.
Forgetting the separation distance
Vaughan and Richmond Hill want 4.0 m between the suite and the house. Newmarket wants 3.0 m. Add the rear setback and a 30 m deep lot loses more yard than people expect.
Parking that does not fit
Newmarket wants the suite’s space outside the garage and within the maximum driveway width. If your driveway is already full, you may not be able to add a legal space without a curb cut.
Skipping the conservation authority
A ravine lot looks perfect for a backyard suite. It is often regulated. A TRCA permit adds time and may move or shrink the building.
Buying a kit before the zoning check
A prefab that is 6.8 m tall does not fit under Newmarket’s 5.5 m one-storey cap. The factory will not take it back. See our prefab vs custom guide.
Not registering
Newmarket, Markham and Aurora all require registration. An unregistered unit can cause trouble with insurance, resale and the fire department, in that order of expense.
Rules of thumb before you spend a dollar
- Get the zoning answer by email, from the town, with your address in it.
- Measure the walk from the curb to where the suite door will be. Over 45 m, start worrying about fire access.
- Find out how deep your sewer lateral is and how big your water service is.
- Ask the building department which charges will be on the permit invoice, including school boards.
- Price the servicing before you price the building. It is the half of the budget nobody shows you. Our servicing cost guide breaks it down.
Find out if your York Region lot works before you pay a designer.
Our $399 + HST Garden Suite Feasibility Report checks your zoning, separation, height, servicing and fire path in 48 hours. The fee is credited toward permit plans.
York Region Garden Suite FAQ
Can I build a garden suite in Markham?
On a serviced urban lot, provincial law allows up to three units, with one in a detached building, and Markham must follow that. Markham did not go further: its four-unit plan was revoked in March 2026. You need one extra parking space for a coach house or garden home, a 1.2 m path to the street, and registration with Markham Fire and Emergency Services. Size and height come from Zoning By-law 2024-19, so get a written zoning answer first.
How big can a detached unit be in Newmarket?
Under By-law 2026-10, a one-storey detached unit can be 10% of the lot area or 75 m2, whichever is less. Two storeys, or a unit over a detached garage, can be 10% of the lot or 100 m2, whichever is less. It cannot be taller than your house and must sit 3.0 m from it.
Can I put two units in my backyard building in Richmond Hill?
Yes. Richmond Hill By-law 143-24 allows up to two ARUs in an accessory residential building, as long as the lot has no more than four units in total. The building can cover up to 80 m2, go two storeys and reach 7.5 m at the peak, and must be in the rear yard 4.0 m from the house.
Do I pay development charges on a garden suite in York Region?
Usually not the municipal and regional charges. Ontario’s Development Charges Act exempts a second unit in an ancillary building where the main house has no more than two units. Education development charges are separate and may still apply. Ask the building department for the expected permit invoice before you budget.
Can I build a garden suite in Vaughan if I am on a well and septic?
Not under Vaughan’s ARU rules. By-law 082-2025 permits ARUs only on lots with municipal water and sanitary services. Rural owners on private services would need to ask Vaughan planning about other options, such as a site-specific application, and should expect a longer process.
Are there pre-approved garden suite plans in York Region?
Richmond Hill offers one pre-approved detached ARU reference model, about 6.64 m by 5.47 m. You still need a site plan for your lot and a declaration form with the permit. We did not find town pre-approved detached plans in Markham, Vaughan, Newmarket or Aurora in October 2026.
Is there a garden suite grant in York Region?
We found no current town grant for detached units in Markham, Vaughan, Richmond Hill, Newmarket or Aurora as of October 2026. Programs change, so check each town’s housing page. Federal and CMHC options are listed in our funding directory.
Do I have to register a garden suite in Newmarket or Aurora?
Yes in both. Newmarket charges a one-time $268.93 registration fee and issues an N plate. Aurora By-law 6660-24 requires each ARU to be registered separately. Markham also requires registration through its fire department.
Will you build my garden suite in York Region?
No. We build in Simcoe County and around Georgian Bay. In York Region we sell the $399 + HST feasibility report, permit packages and paid builder calls, so you go to a local contractor with a checked lot and a clear scope.