New build inspection · Grading and drainage
Grading and drainage defects in a new build
Grading is the defect category that produces the most new build warranty claims in Alberta, because the lot is finished last, often in the wrong season, and a negative slope of even a few centimetres sends water at the foundation for the life of the house.
What goes wrong with grading and drainage in a new build?
Reviewed · 2026-09-03Grading is the defect category that produces the most new build warranty claims in Alberta, because the lot is finished last, often in the wrong season, and a negative slope of even a few centimetres sends water at the foundation for the life of the house.
Why it matters
Grading and drainage in a new home
Almost every part of a new home is inspected by a municipal inspector at some stage. The lot is the exception. Final grade is usually placed months after possession, frequently by a subtrade who never sees the house again, and it is the single detail most likely to cause an expensive problem years later.
Calgary makes this harder than most cities. The soils across much of the city are expansive clay that swells when wet and shrinks when dry, which moves foundations and flatwork. Frost drives moisture toward the foundation in winter, and the spring melt arrives fast enough that a badly sloped yard can put several centimetres of standing water against a basement wall in a single afternoon.
The good news is that grading is one of the few systems a buyer can assess without tools or training. If you can see where water would go, you can inspect it.
Best moment to look
First winter
Grading problems are most visible during the spring melt and after heavy rain. Walk the lot while water is actually moving, photograph it, and file the claim before the first-year coverage expires.
In Alberta
Most Alberta municipalities require a lot grading certificate before the grading deposit is released, and Calgary is one of them. That certificate confirms the lot matches the approved grading plan; it does not confirm that water actually drains away from your specific corner. Ask for a copy, then verify it yourself in the spring. Grading and surface water are covered under the one-year workmanship and materials period of the Alberta New Home Warranty, so the clock is short.
How it should be built
What correct looks like
Where water should go at the foundation
Ground falls away from the wall, the downspout discharges clear of the foundation, the window well drains, and cladding keeps its clearance above grade.
The flags
What to look for
Each item lists what the defect is, how to spot it without tools, and the stage of construction when it is still visible. None of this replaces a licensed inspector. It makes you a useful witness on your own site.
01Negative slope at the foundation
Water and envelopeWhat it is. The ground should fall away from the house on every side. Where it falls toward the house, surface water and melt collect against the foundation wall and load the weeping tile and the damp proofing continuously.
How to spot it. Stand at each corner and look along the ground away from the wall. You are looking for a visible fall over the first two metres. Pour a bucket of water at the wall and watch which way it runs.
Visible at: First winter
02Downspouts discharging at the wall
Water and envelopeWhat it is. A roof sheds a large volume of water into a small area. A downspout that ends at the foundation concentrates it exactly where you least want it, and short factory extensions are routinely left on at possession.
How to spot it. Follow every downspout to its end. The discharge should be well clear of the wall and pointed downhill, not into a window well, a walkway or the neighbour's lot.
Visible at: Pre-possession walkthrough
03Window wells without drainage or covers
Water and envelopeWhat it is. A basement window well is a hole beside the foundation. If it has no drainage to the weeping tile and no cover, it fills with rain, snow and debris and eventually finds the window.
How to spot it. Look into each well. You want clean gravel with no standing water and no soil built up near the window frame, and a cover that actually fits.
Visible at: Pre-possession walkthrough
04Settlement trenches over the service lines
Water and envelopeWhat it is. The trench cut for water, sewer and gas is backfilled loosely and settles for years. A depression that forms along the line becomes a channel that carries water back toward the house.
How to spot it. Walk the line between the house and the street after the first spring. You are looking for a shallow trough, and for water sitting in it rather than draining across the lot.
Visible at: First winter
05Sump pump discharging into the yard
Water and envelopeWhat it is. A sump discharge that ends a metre from the wall pumps groundwater straight back into the ground it just came from, recycling the same water and running the pump continuously.
How to spot it. Find the discharge pipe outside and follow it. It should carry water well away from the foundation, and it should not drain back into a window well or a low spot.
Visible at: Pre-possession walkthrough
06Flatwork sloped toward the house
Water and envelopeWhat it is. Driveways, walkways and patios placed before final grade sometimes end up pitched back at the building. Concrete is expensive to correct once it is cured.
How to spot it. Look at the joint where a slab meets the house. Water should run away from that joint. Watch where puddles form after rain.
Visible at: Pre-possession walkthrough
07Grade covering the cladding or the weep holes
Water and envelopeWhat it is. Siding and brick need clearance to the ground. Soil piled against them wicks moisture into the wall assembly and blocks the weep holes that let a brick veneer drain.
How to spot it. Look at where the wall meets the ground. There should be a visible gap of bare foundation between the soil and the bottom of the siding or the brick course.
Visible at: Pre-possession walkthrough
Put it in writing
Questions for the builder
Ask these by email rather than on site. A written answer is a record, and a builder who answers clearly in writing is telling you something useful about how the rest of the build will go.
- When is final grade scheduled, and does that date fall inside my one-year warranty period?
- Can I have a copy of the approved lot grading plan and the grading certificate when it is issued?
- Where do the downspouts and the sump discharge terminate on the approved plan?
- Are window well drains connected to the weeping tile, and are covers included?
FAQ
Questions about grading and drainage
Grading and surface drainage generally fall under the one-year workmanship and materials coverage rather than the longer structural period. That makes the first spring the critical window: if you wait until the second year to report standing water, you may be outside coverage. Document with dated photographs as soon as you see it.
Building codes and municipal grading plans call for a defined fall away from the foundation over the first couple of metres, then a route across the lot to a swale or the street. You do not need to measure it precisely to see a problem. If water sits against the wall or runs toward it, the grade is wrong regardless of what the plan says.
Some settlement of backfill is normal and expected, particularly over the service trench and around the foundation. What is not acceptable is settlement that reverses the drainage direction and channels water at the house. Report it as a drainage defect rather than as settlement, and include photographs of where the water goes.
Source note
- Sources
- Alberta New Home Warranty program information
- National Building Code, Alberta Edition, as adopted for the permit in force
- City of Calgary building inspection and lot grading information
- Health Canada radon guidance for homeowners
- Jurisdiction
- Alberta, with Calgary-specific notes
- Applies to
- New residential construction purchased from a builder.
- Last reviewed
- 2026-09-03
- Limitations
- General guidance written for buyers, not a code interpretation and not a substitute for a licensed home inspector or a professional engineer. Code requirements depend on the edition in force when the permit was issued. Warranty periods and coverage depend on your own warranty certificate.
- What you should verify
- The requirements that applied to your permit, the coverage periods on your warranty certificate, and any defect with a licensed inspector before you rely on it in a claim.
Work with REP YYC
Bring your own representative to the walkthrough.
The builder's sales staff are paid to sell the builder's lots. REP YYC agents are paid by the builder too, but they work for you: lot choice, contract terms, incentives and the possession timeline. No cost to the buyer.