The finished ground around a house is supposed to slope away from the foundation so rain and snowmelt drain off — a commonly cited target is roughly 150 mm (about 6 inches) of fall over the first 1.5–3 m (5–10 ft). "Negative grading" is the opposite: ground that slopes toward the house, usually made worse by downspouts that discharge right at the foundation.
$500–3,000 regrading / downspout extensions ($5k+ if it caused foundation work)Address soonExteriorStructure
Why it matters
CMHC guidance is explicit that grade should slope away from the structure to direct surface water off the foundation — because directing water to the foundation is the single most common, most preventable cause of wet basements and foundation problems. Water pooling against the wall finds its way in, and over years can contribute to cracking or movement. The fix is usually cheap; the damage if ignored is not, which makes this one of the best value-for-money items a buyer can act on.
How to spot it
Ground sloping toward the walls; mulch, soil, or patios built up above the foundation line; downspouts ending right at the wall with no extension; and inside, pooling, staining, or efflorescence (white mineral powder) on the basement walls below those spots.
What it costs
Often $500–3,000 to regrade low spots and extend downspouts away from the house; far more only if water has already caused foundation or interior damage.
What to do
Address soon — it's high-value-for-cost. Extend downspouts well away from the house, regrade the low spots to slope away, and watch the basement after the next heavy rain.
Education and triage, not a home inspection. Casaroo flags the slope and downspout discharge from your photos — easy to confirm in person and usually inexpensive to correct.
Common questions
What is Negative grading & drainage toward the house?
The finished ground around a house is supposed to slope away from the foundation so rain and snowmelt drain off — a commonly cited target is roughly 150 mm (about 6 inches) of fall over the first 1.5–3 m (5–10 ft). "Negative grading" is the opposite: ground that slopes toward the house, usually made worse by downspouts that discharge right at the foundation.
Why does it matter for home buyers?
CMHC guidance is explicit that grade should slope away from the structure to direct surface water off the foundation — because directing water to the foundation is the single most common, most preventable cause of wet basements and foundation problems. Water pooling against the wall finds its way in, and over years can contribute to cracking or movement. The fix is usually cheap; the damage if ignored is not, which makes this one of the best value-for-money items a buyer can act on.
How can I spot it?
Ground sloping toward the walls; mulch, soil, or patios built up above the foundation line; downspouts ending right at the wall with no extension; and inside, pooling, staining, or efflorescence (white mineral powder) on the basement walls below those spots.
How much does it cost to fix?
Often $500–3,000 to regrade low spots and extend downspouts away from the house; far more only if water has already caused foundation or interior damage.
(site grading and drainage away from the foundation). Casaroo flags, it does not inspect.
Last reviewed 2026-06-27.
Casaroo reviews each guide against current pricing, code, and insurer practice. Cost ranges are 2026
estimates that vary by region, size, and access — confirm specifics with a licensed professional.