Four feet. Five feet. Ten feet. Twenty feet. Those are the downspout drainage distances the first four search results hand a Michigan homeowner, and none of them acknowledges the other three.

They disagree because they answer three different questions. Surface discharge needs to land at least 5 feet from the foundation. A line piped to an underground catchment (a buried basin or dry well that holds water until the soil takes it) needs 10 feet. A buried line running to open ground often needs closer to 20 feet on a flat Michigan lot, where the ground takes that long to fall away.

What that trapped water does to a foundation over a Michigan spring is its own guide. This one is about the fix.

Five Feet, Ten Feet and Twenty Feet Describe Three Different Systems

The US Department of Energy’s Building America Solution Center sets the first two numbers: 5 feet for a downspout discharging at the surface, 10 feet to an underground catchment. Two numbers from one source, because the water ends up in two different places.

The third comes from Michigan drainage contractors on flat clay lots, where a line discharging at 10 feet still empties onto ground that cannot move the water. Their working minimum runs closer to 20 feet, far enough out that the pipe reaches a point where the grade (the slope of the ground) finally falls away.

The real question is not how far a downspout drains, but where the water has to get to on your lot.

Key takeaway: Five feet for surface discharge, 10 feet to an underground catchment, more than either on flat clay.

Michigan Clay Holds the Water You Pour on It

Mid-Michigan is mostly clay, and clay takes water slowly. What does not soak in spreads across the surface instead, and on the flat lots common around Lansing and Owosso it spreads back toward the house as readily as away.

Michigan runs 20 to 30 freeze-thaw cycles in a typical winter, each one expanding the water held against the foundation wall and then releasing it. Water that never leaves keeps getting worked into whatever it sits against.

Grade decides whether an extension accomplishes anything. Residential code asks for 6 inches of fall in the first 10 feet from the house. On flatter ground, a 6-foot extension relocates the puddle by 6 feet.

Key takeaway: Clay, flat lots and 20 to 30 freeze-thaw cycles a winter push the Michigan number past the national one.

A Pitched Extension onto Ground That Falls Away Handles Most Lots

The cheapest version works on most houses: an elbow at the downspout base, a rigid extension carrying water 5 to 10 feet out, and a splash block or regraded landing spot where the ground already falls away. Hardware store parts, an afternoon, no excavation.

Rigid extensions hold their pitch; flexible accordion extensions sag, collect debris, and often move less water than the splash block they replaced. Either needs continuous downhill fall to the discharge point, with no dip where water stands.

Volume matters as much as distance: a downspout draining too much roof overwhelms any extension in a heavy rain, and the rough check is one downspout per 35 feet of gutter run. Gutters that sag, overflow, or pull away from the fascia are failing upstream of the discharge point.

None of it works if the gutter never delivers water to the downspout, and leaves and shingle grit strand more roof runoff than any extension length.

Key takeaway: A rigid, continuously pitched extension onto ground that falls away is the right first move on most lots.

A Buried Line Earns Its Keep on a Flat Clay Lot

Burying the line is right for a specific house: flat lot, heavy clay, finished basement, and no point within 10 feet where the ground meaningfully falls away. It costs far more than an extension and means trenching the yard, so confirm the surface fix cannot work first, the same reasoning as repairing a gutter run rather than replacing the whole thing when a repair will hold.

The Michigan working spec: 4-inch corrugated pipe (ribbed flexible black drain pipe), a trench around 14 inches deep, roughly 10 inches of cover, and continuous slope so the line runs out to daylight (where the pipe opens at the surface) or to a pop-up emitter, a spring-loaded lid set flush with the lawn.

Where the line opens is the whole job. A daylight discharge has to land on ground that carries water away and gives it no path back. Michigan drainage contractors have documented brick veneer separating on a 15-year-old home whose buried line discharged 10 feet out onto flat clay: the pipe worked as designed and still put the roof’s water where it stayed against the house.

Key takeaway: A buried line earns the trench when nothing within 10 feet will take surface water.

A Line That Drains Empty Beats a Line Buried Below the Frost Line

Mid-Michigan’s frost line (the depth frost reaches in a normal winter) sits around 42 inches, and a downspout line buried at 14 inches is nowhere close. A water supply line goes below frost because it always holds water. A drain line pitched to run empty has nothing in it to freeze and split. Slope protects a downspout line, not depth.

The failures show up at the ends of the pipe. A pop-up emitter iced shut backs water up the line toward the house. A shallow section that lost its pitch holds water, freezes, and heaves to the surface. And a February thaw sends a whole roof’s snowmelt onto frozen ground that absorbs none of it, the winter version of gutter and downspout problems that surface after the melt.

Key takeaway: A buried line survives Michigan winters by draining empty, not by sitting below the frost line.

Check With Your City Before Tying Into the Storm Drain

Connecting a downspout to the street drain is not a homeowner’s call. Michigan law requires downspouts to be disconnected from combined sewers (systems carrying sewage and stormwater in the same pipe), because roof runoff there pushes untreated overflow into rivers in heavy rain. Where separate storm sewers exist, connecting is a local decision: East Lansing publishes its own rules, and the next town over may read differently. A call to your building department settles it before anybody digs.

Key takeaway: Michigan bars downspout ties to combined sewers; everything past that is set locally.

What to Check After the Next Real Rain

Go stand outside with an umbrella next time it is really coming down and look at where each downspout puts its water. The one dumping at the foundation onto ground that slopes back toward the house is the one to fix first, and fixing it is usually the cheapest thing you will ever do for your basement.

Have Someone Look at the Whole System

Gutters, downspouts and discharge are one system, and most homeowners only see one end of it. Weather Vane Roofing checks discharge distance, downspout capacity and gutter pitch as part of a free estimate across Lansing, Howell, Brighton and Owosso. If you just want to know whether your 6-foot extension is doing the job, Roofster can answer without anyone coming out.