A concrete driveway usually sinks or slopes toward the house for one of two reasons. Either the slab settled as support washed out or compressed underneath. Or it was poured with the wrong pitch from day one.
You’re noticing it because water now runs toward your garage door or foundation line, a classic negative slope driveway toward foundation symptom. Think of it as channeling runoff straight into your foundation line. The tricky part is that the same symptom can come from very different causes. Poor base compaction or erosion from gutter overflow can do it. In the sections below, you’ll learn how to tell “settlement” from “negative slope,” and what to fix first so you don’t pay to lift or replace concrete while the ground beneath it is still washing out.
What’s Happening: Sink vs Negative Slope
If water runs toward your garage or foundation line, you’re usually dealing with one of two realities: the slab dropped (settlement) or the slab is still “where it always was” but the surface geometry sends runoff the wrong way (negative slope).
| Quick read | Settlement (slab dropped) | Negative slope (wrong pitch) | What it points to first |
|---|---|---|---|
| What you’ll notice | Localized low spot, corner/edge lower, “step” at a joint | Whole panel pitches toward the house without a distinct drop | Sink vs pitch problem |
| Common telltales | New trip lip, widening control-joint gaps, one panel lower than adjacent | Consistent slope toward wall, no single low corner or joint step | Geometry vs movement |
| Typical causes | Void/washout, poor base compaction, erosion from misdirected runoff | Poured with wrong pitch from day one (or regrading changed runoff path) | Fix water/base vs re-slope/drainage |
Don’t automatically call it “sinking” just because you see water at the wall.
Check it fast: kick the tires by laying a 4–6 ft straightedge or level across the area that looks wrong to measure driveway slope toward house and look for a low spot or a step at a joint. If you see a new trip lip or widening gaps at control joints, you’re seeing settlement. If the whole panel reads as a consistent pitch toward the house with no localized drop, it’s a slope problem, not a sink.
The Most Common Causes
You patch the surface and the water still shows up at the garage edge after the next hard rain, because the real problem was never on top of the slab. That is why a small drainage miss often becomes ongoing slab movement.
Most driveway “sinking” starts under the concrete: concrete driveway settling under slab from a base that wasn’t compacted well enough, or soil that later got softened and displaced. In coastal North Carolina, sandy subgrade and wet periods can turn small voids into real settlement, especially at slab edges.
The most repeated real-world trigger is water mismanagement, and it is the one you cannot afford to ignore.
Overflowing or clogged gutters are a common way roof runoff gets dumped right where it can wash out the base under a driveway edge. Read more in our article: Safely Clean Gutters For example, a downspout that dumps beside the driveway or a gutter that overflows at one corner can wash fines out from under the slab and create an edge void at the garage apron. If you treat this like a surface pitch problem only, you can end up paying to “fix” concrete that’s still being undermined.
What to do next (fix cause before lifting)
Many builder and code-referenced guides call for driveway slope drainage away from house of about 1%–2%, and surrounding grade to drop roughly 6 inches over the first 10 feet. If your driveway runs the opposite direction, tiny errors in runoff control get amplified fast.
Before you pay to lift or replace anything, first stop the thing that is still stealing soil from under the slab. It behaves more like constant erosion under the slab than a surface issue you can patch. Verify gutters aren’t overflowing and confirm every downspout has extensions that discharge well away from the driveway edge.
Downspout discharge that’s too close to the foundation can quietly concentrate water and accelerate soil loss along slabs and garage aprons. Read more in our article: Clean Gutters Downspouts The move most homeowners skip is fixing roof runoff first, then re-checking movement; if you lift concrete while water keeps cutting a void, you’re buying a repeat problem.
Use slope targets as a plain-language spec when you call contractors. DIY vs. call a pro usually comes down to whether you can hit 1%–2% (roughly 1/8–1/4 inch per foot) away from the foundation, plus about 6 inches of fall over the first 10 feet of surrounding grade. If your lot is steep or boxed in, don’t assume “make it slope away” is the only answer; a trench drain in front of garage that intercepts runoff and sends it to a legal discharge point can outperform regrading. Choose lifting when the panel is intact but dropped from voids, and replacement when it’s badly broken or the base is clearly failing.
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