How to Read an Ontario Survey Like You Actually Own the Place
A survey can look like someone spilled spaghetti on graph paper. But it’s really just a legal map: boundaries, evidence, and the “you can’t build here” zones hiding in plain sight.
What a survey is (and what it is not)
An Ontario survey plan is prepared by an Ontario Land Surveyor, and it’s built on research plus physical evidence—not vibes. It’s not a grading plan, not a building permit, and not proof your fence is right. Think of it as: “Here’s what the land records and the evidence on the ground say your boundaries are, and here are the interests that affect them.”
Three plan types you’ll run into
- Registered Plan of Subdivision: creates lots; shows dimensions and monuments.
- Reference Plan (R-Plan): deposited plan showing “Parts” for severances/easements/road widenings; it may not mean the land is buildable.
- Surveyor’s Real Property Report (SRPR): often shows buildings and highlights encroachments/interests.
Step 1: Title block first (this is where adults start)
Before you zoom into the squiggles, read the title block. You’re looking for the plan type and number, the surveyor’s name/date, the legal description, the scale, and the north arrow. This tells you what document you’re holding and whether it matches the parcel you care about.
Step 2: Find the legend (a.k.a. the translation key)
Surveys use abbreviations because surveyors have better things to do than write novels. In Ontario you’ll commonly see monument abbreviations like IB (iron bar), SIB (standard iron bar), SSIB (short standard iron bar), and CC (cut cross). The legend is where those symbols get explained—so you know what’s supposed to be in the ground.
Found vs set: why those two words matter
Found means the surveyor located existing evidence. Set means a monument was planted/re-established based on records and evidence. Either way, don’t assume “the corner is exactly where the PDF line looks.” On many properties, the physical monument is the star of the show, and the measurements are the supporting cast.
Builder translation: don’t “fix” a boundary with a tape measure. That’s how neighbour disputes are born.
Step 3: Read the boundary lines like a builder
Your boundary is usually the heavy outline (or the line called out as the limit of the parcel). Along it you’ll see bearings (direction) and distances (length), typically in metres. Plans often include notes about grid bearings, ground distances, and scale factors—because the plan uses a defined reference system. Ontario rules for survey practice also describe how bearings can be determined (for example, from GNSS observations, from a known line with evidence, or from monuments tied to a coordinate system). In other words: the numbers aren’t random.
If you’re trying to decide “Can I fit a garage here?” your quick win is identifying where the corners are and how long each boundary is. That’s the foundation of setbacks, building envelope, and everything that costs money.
Step 4: Hunt for easements and rights-of-way (the sneaky stuff)
Many plans show physical or documentary evidence that affects title—like fences, retaining walls, and especially easements and rights-of-way. These can appear as labelled strips, notes, or references to registered instruments. If you see an easement running down the side yard, that’s not decoration. It can restrict what you’re allowed to build or where you can put services.
The 5-minute survey checklist I use on site visits
If you can’t check these off, you don’t need to panic—you need to ask questions before you build.
Turning a survey into real costs
A survey is where “I want” meets “I’m allowed.” Easements can push a house footprint, long boundaries can mean longer services, and tight geometry can force design changes. If you’re early in planning, ballpark tools help you keep the budget honest (before you fall in love with a lot that fights back):
Quick tools
And if you’re thinking ICF walls (bigger planning pay-off), there’s more here: ICFPRO.ca.
FAQ
Is my fence automatically the property line?
No. Sometimes it’s close, sometimes it’s “close-ish,” and sometimes it’s wrong. Use the survey to understand the legal boundary evidence before you build to a fence line.
Does a reference plan mean the lot is buildable?
No. A reference plan is a deposited plan used to describe parts of land and interests (like severances and easements). Buildability depends on zoning, setbacks, and servicing approvals.
When do I need a survey before building?
If you’re building near a boundary, adding a garage/deck, or there’s any risk of an encroachment, accurate boundary info is usually cheaper than fixing a mistake after concrete is in the ground.
What should I do if the plan is confusing?
Start with the title block and the legend. Then identify corners/monuments and any easements. If it’s still unclear, don’t guess—get the right professional to interpret it before you build.