✓ The Decision — How to Approach Your Grading Plan
- On a subdivision lot: your grading plan must conform to the developer's engineered master grading plan — the corner elevations, swales, and drainage direction are already designed for the whole street. Replicate that intent; don't redesign where the water goes.
- On a rural or infill single lot: there's no master plan, so your designer grades for positive drainage away from the foundation and to a legal outlet per the local building code — and keeps runoff off the neighbours.
- Either way, build the grade you drew. The plan is checked at a rough grade and a final grade inspection; getting the as-built grade certified is what releases your deposit and, often, occupancy.
- When unsure, ask before you dig: the municipality's lot-grading bylaw (and, in a subdivision, the approved engineering) is the answer that counts.
A grading plan is the drawing that answers one question: where does the water go? It maps the existing and proposed ground elevations across your lot and shows surface water draining away from your foundation, around the house, and out to a legal outlet — the street, a rear swale, or a storm system. It's a small drawing with big consequences: get it right and your basement stays dry and your deposit comes back; get it wrong and you're looking at a wet foundation, an ice problem at the wrong door, a dispute with the neighbour whose yard you flooded, and a final grade inspection you can't pass.
Lot Development Estimator What a Permit Application Needs
What a Grading Plan Actually Shows
Names vary by municipality, but the content is consistent. A residential grading plan typically shows:
- Spot elevations at the lot corners, building corners, and high/low points — existing and proposed — so the reviewer can see the slopes.
- Drainage arrows and slopes showing which way surface water runs and at what grade (expressed as a percentage).
- Swales — the shallow channels that carry water along side or rear yards to the outlet — with their own minimum grade.
- The lot's drainage type — how the lot is meant to shed water within the subdivision scheme (see below).
- Outlets and features — where water leaves the lot, plus downspout/sump discharge points, window wells, walkouts, and retaining walls.
The Key Distinction: Subdivision vs Rural Lot
This is where most homeowners get it wrong, and it changes everything about how the plan is drawn.
Subdivision lots — you conform to an engineered scheme
When a subdivision is designed, the developer's engineer prepares a master grading and drainage plan for the whole development: where every lot drains, where the swales run, the boulevard and street elevations, and the storm outlets. Your lot is one cell in that designed system. So when your architect or designer draws the grading plan for your house, it must replicate the intent of the engineer's subdivision grading — the assigned corner elevations, the swale locations, and the direction water is supposed to travel. You generally cannot decide to send water a different way; doing so breaks the street's drainage and is the fastest way to fail review or end up liable for your neighbour's wet yard.
Subdivision lots are usually assigned a drainage type, such as:
| Type | How the lot sheds water |
|---|---|
| Back-to-front | Runoff drains from the rear of the lot toward the street/storm system at the front. |
| Front-to-back | Runoff drains from the front toward a rear swale or rear catch basin. |
| Split drainage | A high point partway back splits the lot — front portion drains to the street, rear portion to a rear swale. |
Your plan has to honour the type your lot was assigned. The swale between you and your neighbour, for example, is shared infrastructure — filling it in or regrading across it is a classic violation.
Rural and infill single lots — you design for code-compliant drainage
On a rural property or a one-off infill lot, there's usually no master plan to conform to. Here the architect or designer draws the grading to ensure positive drainage away from the foundation per the local building code, carries that water to a legal outlet (a ditch, a swale, or natural drainage), and — critically — doesn't dump concentrated runoff onto the neighbouring property. The freedom is greater, but so is the responsibility: with no engineer's scheme backing you up, the drainage logic has to be right on its own.
The Drainage Rules That Matter
- Slope away from the foundation — about 2% minimum. Canadian practice (and the building code's intent that water not accumulate at the foundation) is finished ground sloping down and away from the building at roughly 2% or more, for both the rough grade and the final grade, past the backfill zone. Too flat and water sits against the wall; the backfill settles, and you've made a bowl.
- Swales need grade too. The channels carrying water along your yard have their own minimum slope so they actually drain instead of ponding — confirm the figure your municipality uses.
- Keep your water on a legal path. Runoff must reach an approved outlet; you can't concentrate it onto a neighbour or block an existing drainage route.
- Discharge downspouts and sumps to grade, not against the wall. Where they let out matters as much as the slope.
Who Prepares It — and the Certificate & Deposit
In practice, the grading plan is usually drawn by the architect or designer preparing your building permit drawings. In a subdivision, that drawing replicates the engineer's approved subdivision grading; on a rural or single lot, the designer lays out code-compliant drainage away from the foundation. The municipality's lot-grading bylaw is what governs, and in a subdivision the developer's engineering drawings are the reference.
Two more pieces complete the picture:
- Grading inspections. Many municipalities inspect a rough grade (after backfill) and a final grade (after landscaping). The as-built grade has to match the approved plan.
- The grading certificate and deposit. A lot-grading certificate — often prepared by a surveyor or engineer — confirms the as-constructed grades match the plan, and is what satisfies the final inspection. Municipalities commonly hold a grading deposit (frequently a few thousand dollars) that's refunded only once the final grade is certified. Fail to certify and the deposit — and sometimes occupancy or release of other holds — is at risk.
The cost of the physical grading — the cut, fill, and building pad — is a separate budget item; see the real cost of developing a rural lot and price it with the Lot Development Estimator. Because grading-plan, certificate, and deposit charges vary widely by municipality, confirm those locally. Knowing exactly what your municipality's lot-grading bylaw requires before you design is the kind of question a focused feasibility review answers — and it's cheaper than redrawing.
✗ Deal-Breakers — Don't Grade Past These
- Contradicting the subdivision drainage scheme. Regrading across a shared swale or sending water a different direction than the engineered plan breaks the street's drainage — it fails review and can make you liable. Conform to the approved plan.
- Negative drainage toward the foundation. Any slope back toward the house — or a flat grade that settles into one — is a wet-basement machine and an automatic inspection failure.
- Dumping runoff onto the neighbour. Concentrating your water onto the adjacent lot is both a bylaw violation and the most common neighbour dispute in new subdivisions.
- Skipping the final grade certificate. Landscaping over an uncertified grade can forfeit your deposit and stall occupancy — get the as-built certified.
The Safest Path Forward
- Get the controlling drawing first — in a subdivision, the approved engineering grading for your lot; elsewhere, your municipality's lot-grading bylaw.
- Have your designer replicate that intent — corner elevations, swales, and drainage direction — on the grading plan that goes with your permit.
- Build to the grade you drew, sloping at least 2% away from the foundation and keeping swales clear.
- Book the rough and final grade inspections and get the lot-grading certificate so your deposit is released.
- Keep the certified plan — it resolves future drainage or neighbour questions, and it's a resale asset.
Bottom Line
A grading plan is small but decisive: it proves your lot sheds water away from your foundation and out to a legal outlet without harming anyone downhill. On a subdivision lot you conform to the developer's engineered scheme; on a rural lot you design code-compliant drainage from scratch — and in both cases the as-built grade has to be certified before the deposit comes back. Confirm your lot's requirements with the municipality, then make sure the grading plan in your permit package matches what gets built. And once the lot sheds water, decide where the roof water goes — see Roof & Lot Drainage.
Frequently Asked Questions
What is a residential grading plan?
It's a drawing showing existing and proposed ground elevations across a lot, with drainage arrows, slopes, and swales that direct surface water away from the foundation and out to a legal outlet. Municipalities use it to confirm a property drains correctly before and after construction.
How much should the ground slope away from my foundation?
Canadian practice is finished ground sloping down and away from the building at roughly 2% or more, for both rough and final grading, past the backfill zone — enough that water never accumulates at the foundation. Confirm the exact figure with your municipality.
Can I change the grading on my subdivision lot?
Generally no. Subdivision lots are graded to a developer's engineered master plan, and your grading must replicate that approved drainage — the assigned elevations, swales, and drainage direction. Changing where water goes breaks the street's drainage scheme and typically fails review.
What is a lot-grading deposit, and how do I get it back?
Many municipalities hold a deposit (often a few thousand dollars) at permit time to ensure the lot is graded correctly. It's refunded once your final grade is built to the approved plan and certified — usually by a surveyor or engineer — and the municipality's final grade inspection passes.