Sault Ste. Marie drew a hard line this September. Milton drew none. Milton’s council voted on Monday, September 14, 2026 to study data centres and refused to pause them during the study. Sault Ste. Marie’s council answered on Monday, September 21 with an interim control by-law prohibiting any new data centre over 50 megawatts. Both councils worked from the same section of the same provincial law, and the two towns operate under opposite rules while the province’s playbook remains an unreleased draft.
The distance between those decisions is the story Ontario is writing this fall, one council agenda at a time. Oakville had already passed its own one-year control by-law on August 11, before any formal application had reached that town. Four municipalities have now answered a provincial question locally, because no provincial land-use answer exists yet.
The short answer. Section 38 of Ontario’s Planning Act lets a council prohibit a land use for up to one year while the municipality studies that use and writes its rules. Milton took the study and declined the prohibition, so applications there continue under existing rules. Sault Ste. Marie took both halves, passing By-law 2026-138 to prohibit new data centres over 50 megawatts for one year while its framework is written. The province’s draft Data Centre Playbook governs grid connections only, and its comment period closed September 12.
This fall, the binding Ontario rulebook on data centres is a stack of municipal by-laws, and no two pages in the stack draw the same line.
- What did Sault Ste. Marie pass on September 21?
- What did Milton decide seven days earlier?
- Is this local control working, or a patchwork nobody can price?
- Where does an operator look for the rule that actually binds?
What did Sault Ste. Marie pass on September 21?
The by-law measures a site the way a meter does: add the maximum electrical demand of everything on it, buildings, cooling, backup equipment and accessory uses together, and a total over 50 megawatts makes the facility a large-scale data centre in the by-law’s eyes. While the by-law is in force, no person may use land or buildings anywhere in the city for such a facility, and no existing centre may expand across the line. A centre lawfully operating at or under 50 megawatts may continue, and the by-law holds for one year from the day it passed. It ends earlier if council repeals it, it can be extended under the Planning Act, and it gives way if a municipal framework is approved first. Council had set this course on August 31, when a motion directing staff to prepare the by-law carried ten votes to none.
The same meeting carried the study the prohibition is buying time to finish. Staff brought council a draft planning framework, with a recommendation to send it to formal public consultation. Under the draft, a facility under one megawatt is an accessory information-technology use, and one from one megawatt to just under five proceeds under site plan control, with an agreement and studies behind it. Every data centre at five megawatts or more becomes a restricted land use, permitted only through a rezoning application. The studies it demands from qualified professionals run from the grid outward: electrical capacity, water supply and fire flow, stormwater, emergency power and fuel storage, and compatibility and noise last. It requires municipal water and sewer connections, bars data centres from the rural area, and demands water-efficient cooling. It requires consultation with First Nations and at least one neighbourhood meeting before any large project proceeds.
What did Milton decide seven days earlier?
Milton’s council had the same instrument on its table, preserved in the town’s own meeting record for September 14. Councillor Sameera Ali’s motion asked council to bring forward an interim control by-law under section 38, prohibiting major digital infrastructure facilities across the whole town for one year. The stated purpose was time, so the town could complete a planning study and build a framework for managing such facilities. The motion required staff to report back before the by-law expired, and it allowed one extension of a single additional year, and no more. It reached the floor as a notice of motion, with procedure rules waived for the night.
Council split the question in two and answered the halves in opposite directions. The study half carried, and staff are now examining the planning and infrastructure implications of hyper-scale data centres for a made-in-Milton framework. The prohibition half failed, so no interim control by-law stands between an applicant and the ordinary planning process. Mississauga’s council reached the opposite conclusion two days later, passing a city-wide control by-law on September 16. (Mississauga Had One Data Centre Application. It Froze Every Lot in the City.)
Is this local control working, or a patchwork nobody can price?
Count the September record two ways and it argues with itself: one prohibition, one refusal, one provincial draft still unreleased. The first holds that local control is democracy working as designed, because land, water, noise and grid capacity are local facts. The Planning Act hands the section 38 pen to councils on purpose, and each town read its own conditions before ruling. The second holds that local control has produced a patchwork no builder and no resident can price in advance. A project that clears the line in one municipality can be prohibited in the next for reasons unrelated to its design. Both readings describe the same record accurately, and the difference between them sits in a chair neither council occupies. Land use in Ontario is municipal by design, and the only provincial instrument in force speaks to grid connections, under Bill 40. The draft playbook would assess new projects against three provincial priorities, covering economic development, data security and public trust. Until a final playbook lands, section 38 remains the only operative rulebook on land use, and it belongs to whichever council is in session. Ottawa reached the same conclusion from the opposite direction when it published its principles this month. The patchwork has an author, a province that has announced a framework and not yet released it. Ottawa Set Five Expectations for Data Centres. The Switches Sit Elsewhere.
Where does an operator look for the rule that actually binds?
The fixed points in this file are printed, and none of them sits inside a proponent’s project plan. Sault Ste. Marie’s framework returns to council for approval in the first quarter of 2027. The prohibition behind it runs to September 21, 2027, unless the framework arrives first and replaces the by-law outright. The province has tied its final playbook to the fall release of its AI industrial strategy, a season with no date attached. Anyone pricing an Ontario site this year should read the municipal record before the provincial one, every time. The rule that governs a parcel sits in a council’s by-law register, and the price should reflect the rule actually in force.
The calendar belongs to councils and to the province, and no project schedule can move a date on it. September 21, 2027 arrives on its own schedule whether a framework is ready or not.
Recap. Milton voted on September 14 to study data centres and refused a one-year town-wide prohibition while that study runs. Sault Ste. Marie voted on September 21 to prohibit new data centres over 50 megawatts for one year, with a draft framework due back for approval in early 2027. Ontario’s draft playbook covers grid connections only, its comment period closed September 12, and the land-use pen remains in council chambers.
Read the running record these votes sit on: Canada’s data centre map: what is built, what is blocked, what is waiting.
