Drainage & Slope Planner
Standing water on a slab almost always traces back to slope. Enter the rise and run over a section of driveway, patio, or pad to check it against the long-standing 1/8-inch-per-foot minimum drainage slope — the same reference we cite on our Concrete Driveways page.
This checks your entered rise/run against the published 1/8 in per foot (about 1%) minimum drainage slope for concrete flatwork. Limitations: it does not know where the water is supposed to go, whether the surrounding grade actually carries it away, or whether a much steeper slope (beyond what's needed to drain) creates its own erosion or runoff problem on your lot — use it as a first check, not a final grading plan.
Where the 1/8 in/ft number comes from
A minimum slope of about 1/8 inch of fall per foot (roughly 1%) is the long-standing reference from concrete industry mix-design and construction guidance (cement.org). Below that, water tends to sit on the slab instead of running off — a common complaint on the flatter lots found throughout South Lake County.
Common drainage fixes
Channel drains
A narrow trench drain with a metal or plastic grate, set into the low point of a slab or at a garage/entry threshold, to catch and carry away sheet flow before it pools.
Catch basins
A boxed drain set at a specific low point, connected to buried pipe that carries water away from the slab and house to a safe discharge point on the lot.
French drains
A gravel-filled trench with a perforated pipe that collects and redirects groundwater or runoff moving through the soil next to a slab, rather than water sitting on top of it.
These are the drainage solutions most commonly discussed for flooding or pooling driveways and slabs. If the underlying problem is the overall grade of the lot rather than the slab itself, a retaining wall sized to manage slope and runoff may solve more than a drain alone.