An ADU rule is useful only when it is tied to the correct property and decision-maker. Start with the civic address, but verify the parcel and legal description before treating a zoning result, map, or listing as applicable. A single property can involve several authorities: the office responsible for zoning may differ from the building department, fire authority, conservation agency, utility, or land registry.
Resolve the property before researching the rule
Collect the full civic address and any parcel or lot identifier shown on a tax notice, deed, survey, or official property record. Compare the address against the parcel map and the legal description in the relevant land record. A geocoded point can land on the wrong side of a parcel line or administrative boundary; a street address may also be assigned differently in planning and utility systems.
Use the record system for the location. For example, Ontario’s land registry provides access through OnLand to current and historical property records, plans, and instruments. Alberta’s title system identifies fields such as the legal land description and LINC or title number. British Columbia’s Land Title and Survey Authority offers title searches and land-title records. These are jurisdiction-specific examples, not interchangeable national systems.
Canadian parcel services also use different identifiers and have different map limits. In British Columbia, LTSA says a title search uses a nine-digit Parcel Identifier (PID), which may be found through ParcelMap BC, BC Assessment, or a tax notice when it is not already known. Nova Scotia’s Property Online guide warns that its parcel maps show approximate location and configuration and are not surveys or conclusive boundary records. Manitoba’s map guide lists several possible search keys, including an assessment roll number and a legal land description, and cautions that map data depend on scale, date, and source interpretation. These examples help locate records; they do not establish a common Canadian parcel system.
New Brunswick’s GeoNB viewer combines property and civic-address data from different agencies with different stated update cycles, so note the layer’s date and responsible agency. Québec distinguishes staking—which places markers based on a surveyor’s opinion—from a formal boundary determination based on deeds, the cadastral plan, and review of neighboring limits. If a boundary will determine where a building can go, ask the relevant authority or survey professional which record or process resolves it.
If the address, parcel identifier, legal description, and mapped boundary disagree, preserve the discrepancy. Do not select whichever result is easiest to find. Ask the local assessor, planning office, land registry, surveyor, or other responsible office which identifier and boundary should be used for the question at hand. A survey or professional title review may be needed to resolve a line or instrument; an online map does not certify either.
When a property-history search matters, use the environmental record systems for the responsible program and location. Their coverage varies, and a blank search is not a clean-site finding; the contaminated-site record guide explains the main U.S., Canadian, and England routes. Alberta water-well records may plot older wells at a legal subdivision or quarter-section centre when coordinates were not submitted, and some older wells may not appear. During Alberta subdivision or development-permit planning, identify abandoned wells under the current AER Directive 079 process and confirm their actual location and requirements with the appropriate authority.
Identify an authority for each question
Build a short authority list rather than assuming that one “planning department” decides everything:
| Question | Possible record or authority to identify |
|---|---|
| Zoning, land use, and local plan | Municipality, county, planning board, or other planning authority |
| Building permit and inspections | Building department or delegated authority |
| Fire access or fire-code review | Fire authority or building official, depending on local process |
| Flood, wetland, conservation, or shoreline | Relevant local, state/provincial, federal, Tribal, or conservation authority |
| Agricultural or heritage designation | The agency or local office that administers the designation |
| Water, sewer, septic, or electricity | Utility or health authority responsible for that service |
The authority can vary by administrative boundary and by project. In Ontario, provincial policy and legislation sit alongside municipal official plans, zoning by-laws, and planning decisions; approval authorities can also have a role. In England, the local planning authority is central to planning questions, while separate bodies may administer designated assets or environmental constraints. Confirm the actual issuing or decision-making authority for your address rather than inferring it from a city name.
England’s Planning Data map can search by postcode, Unique Property Reference Number (UPRN), or local planning authority; its API can return selected constraint layers for a UPRN or coordinate. This helps route a search but does not prove that every local record is covered or that a mapped result controls a proposal. Follow the relevant authority and source document before treating the result as applicable.
Keep public rules and private records separate
Parcel and jurisdiction research establishes where to look; it does not settle every restriction. Public zoning and permit records do not replace title instruments, easements, association or strata documents, lender conditions, or insurance terms. Check those separately, as well as any specialist determination the site may require.
Record the source, identifier, authority, date or version, and unresolved discrepancy for each result. Until the parcel and the relevant authority are confirmed, treat the result as a research lead—not a conclusion that an ADU is allowed or approved.