Downspout Drainage: Where Should Your Downspouts Drain?

Why Dumping Water At The Base Of The House Is So Damaging

A roof is a big funnel. A 1,600 square foot roof in a 1-inch rain sheds roughly 1,000 gallons, and most homes split that between four or five downspouts. So every meaningful rain drops a couple hundred gallons within inches of your foundation wall.

Three things follow.

Basement seepage. Saturated clay against the wall builds hydrostatic pressure. Water finds the cold joint where the slab meets the wall, an old tie rod hole, or a hairline crack. Most "mystery" damp basements we get called about in Madison, Sun Prairie and Verona aren't foundation failures. They're downspout problems.

Soil movement under the footing. Clay swells wet and shrinks dry. Cycle that at one corner for fifteen years and you can get stair-step cracking in block and doors that stick on that end of the house.

Winter ice. The Wisconsin special. A warm January afternoon melts snow on the roof, the downspout dumps it on the walk, and it refreezes by dinner. Now you have a slick slab where people walk, plus water forcing into the soil against the footing at the worst time of year.

There's a quieter fourth: constant splash-back rots siding, trim and rim joists at grade, and it keeps mulch beds wet enough to invite carpenter ants.

The Working Rule: 4 To 6 Feet Minimum, Plus Slope

Two numbers to hold onto.

Discharge distance: 4 to 6 feet minimum. Go to 8 to 10 feet when you have:

• Heavy clay or clay till (most of Dane County)
• A downspout on the uphill side of the house
• A finished basement you can't afford to lose
• A walkout or lookout basement where the grade is tight
• A tuck-under garage where water can run in under the slab

Grade: 6 inches of fall in the first 10 feet from the wall. That's the standard builders are supposed to hit, and it's why a lot of extensions don't work. Run a pipe 8 feet out into a low spot and you just moved the puddle 8 feet. Check yours with a level on a straight board, or watch where a garden hose runs.

Quick decision guide

First, Make Sure The Gutter Isn't The Real Problem

Before you spend money moving water away from the house, confirm the water is actually getting into the downspout. Half the "drainage" calls we take are capacity problems.

Stand outside during a hard rain (or run a hose into the trough) and look for:

• Water sheeting over the front edge of the gutter mid-run
• Overflow at an inside corner where two roof planes dump into one short section
• A downspout that never runs full while the gutter is spilling
• Rust streaks or stained siding under one spot, the fingerprint of years of overflow

Rule of thumb: one downspout per 30 to 40 feet of gutter, more where a big roof plane or a valley empties into a short run. A 5-inch K-style with a 2x3 downspout handles a typical ranch. A steep or large roof usually wants 6-inch trough with 3x4 downspouts, which carry roughly double the water. Our 5-inch vs 6-inch gutter comparison walks through when the upsize is worth it, and gutter drainage solutions covers system-level failures like backpitch and sagging hangers.

Your Options, Cheapest To Most Permanent

Cost at a glance

1. Splash blocks

Good for one thing: keeping water from digging a hole in the mulch. A splash block moves water maybe 18 inches. That's not 4 feet. Use them as a landing pad under a real extension, not as the fix.

2. Hinged or roll-out extensions

The cheap honest fix. Six or eight feet of aluminum hinged extension, flipped up to mow and down after. They work.

Downsides: visible, easy to run over, and roll-out sleeves tear after a couple seasons. Get 6 feet or longer, not the little 2-footers.

3. Buried solid PVC to daylight

The permanent answer and what we install most. Solid PVC, glued fittings, buried shallow, pitched continuously, coming out at daylight down-grade: a low spot, the edge of a swale, a ditch line, a terrace.

Details that separate a good install from a callback:

• Solid PVC, not corrugated flex. More below.
• Continuous pitch, 1/8 to 1/4 inch per foot minimum. No bellies, no flat runs.
• A cleanout or removable connection at the downspout so the line can be flushed or snaked.
• An open, protected outlet that can't pack with leaves.
• Sweeping 45s instead of hard 90s so debris keeps moving.

4. Dry wells and infiltration pits

For a flat lot or a house that sits in the low spot. A gravel-filled pit or plastic chamber wrapped in filter fabric, sized to the roof area feeding it, set well away from the foundation.

Honest caveat: dry wells only work if the surrounding soil accepts water. In tight Dane County clay they can fill and stay full, which in winter means a frozen block of nothing. Test percolation first, and never place one within 10 feet of the foundation.

5. Storm sewer connection (where permitted)

Some Madison-area streets, especially in newer subdivisions, have storm laterals or curb-line drainage intended to take roof water. Where that exists it's a clean permanent solution. Confirm with your municipality's engineering department before anything gets connected. Rules vary block to block.

What if the lot is flat and percolation fails?

This is the real question on a lot of older Madison city lots, and there is an answer. In order of what we try: cut a shallow grassed swale that carries water to the terrace or curb line where allowed; build a properly sized rain garden 10 or more feet out from the wall; or, on the tough ones, install a small below-grade catch basin with a pump that lifts water to a discharge point. That last one adds a pump to maintain, so it's the last resort.

Not sure which tier fits your lot? A walk-around takes about twenty minutes and costs nothing. We'll tell you straight whether you need a $30 extension or a buried line, and we're glad to say "just do the cheap fix" when that's the truth. Request a free inspection here or call the number at the top of the page.

How Much Does It Cost To Bury Downspouts In Madison?

Most single buried runs in our area land between $600 and $2,500, and the spread comes down to length, whether we cross hardscape, and how many downspouts feed one line.

Here's a real anchor. A 35-foot run off a rear downspout on a typical Sun Prairie subdivision lot: 4-inch SDR-35 solid PVC, one sweeping 45, cleanout at the downspout, daylight outlet at the back swale, sod cut and reset, no driveway or sidewalk to cross. That job prices right around $900-1,100.

What pushes it up:

What pushes it down: a short run, open lawn, and a grade that already falls away.

Gutter capacity work often gets bundled in, and pricing for that side is broken out in our gutter installation cost guide.

Where Should The Sump Pump Discharge Go? (And Can It Share The Line?)

Short answer: sump discharge belongs 10 feet or more from the foundation, on its own dedicated line, never tied into the buried downspout line.

Here's why the shared line is a bad idea in Wisconsin. Your sump can run in mid-January during a thaw, when the downspout line may be holding an ice plug or a snow-packed outlet. Push water into a blocked pipe and it comes back where it came from, which is your basement. Combine that with a heavy rain when both systems are running full and you've built a bottleneck.

Do it this way instead:

• Dedicated discharge line, solid PVC, pitched to drain dry
• Daylight 10 feet or more out, onto ground that falls away
• A winter bypass: a removable above-grade hose or extension so the pump has somewhere to go if the buried line ices
• Never into the sanitary sewer, and never back into the footing drain

If your sump runs constantly after every rain, that's usually a downspout problem in disguise. Get the roof water 6 feet out and a lot of sumps go quiet.

Frozen Downspouts, Ice At The Eave, And What They Mean

A downspout freezes from the bottom up. Meltwater trickles down, hits the cold elbow or the buried outlet, freezes, and the plug climbs the pipe. Once the drop is blocked, the trough backs up, the water freezes in the gutter, and now you have a 200-pound ice trough hanging off your fascia.

Important distinction: frozen gutters don't cause ice dams. Attic heat loss and weak ventilation do. Snow melts on a warm deck, runs down to the cold eave, and refreezes there. A blocked downspout and a packed gutter just make the ice at the eave bigger and give backed-up water more time to work under the shingles.

If you get ice at the same eave every winter, the fix is up in the attic (insulation, air sealing, ventilation) and at the eave (ice-and-water shield on the next roof), not in the gutter. Our residential roofing page covers that side of it.

Two things that help right now: keep the downspout outlet and the ground around it clear of snow piles and plow windrows, and swap the problem downspout to a removable above-ground extension for the winter so meltwater bypasses the buried line entirely.

Gutter Guards And Strainers: The Real Cause Of Buried-Line Plugs

Almost every plugged buried line we snake was fed by a gutter full of leaves. That's the number one callback cause, and it's upstream of the pipe.

If you're burying a line, deal with leaf load at the same time. Well-installed gutter guards keep maple seeds, needles and leaf sludge out of the trough, so what enters the pipe is mostly water and a little roof grit that a properly pitched line flushes on its own.

A wire strainer basket in the downspout outlet is a mixed bag. It stops leaves, but only if you pull and clean it every fall. Ignore it and it becomes the clog. Under big oaks and silver maples (hello, most of Madison's older neighborhoods), guarding the gutter beats plugging the drop.

Why Corrugated Flex Pipe Fails Underground

That black ribbed pipe from the big box store is the most common thing we dig up and replace.

The ribs that make it flexible turn the inside wall into a row of little catch basins. Granules, roof grit, needles and silt settle in every rib. In a few years the line is half plugged, and a snake cable hangs up on every ridge.

The thin wall also crushes under backfill, a lawn tractor, or a delivery truck across the terrace. Once it flattens it holds standing water, which brings us to freezing.

Solid PVC (SDR-35 or Schedule 40) has a smooth bore that self-scours, glued joints that don't pull apart with frost movement, and it can be snaked or jetted. A little more in material, and the difference between twenty-five years and five.

The Wisconsin Freeze Detail

Code frost depth in the Madison area is 48 inches, and penetration can approach that in a hard winter. You can't bury a downspout line below frost and still daylight it, so the rule is different: the line must empty completely after every rain.

A pipe with continuous fall drains dry and can freeze all it likes, because there's nothing in it. A pipe with a belly holds a slug of water, that freezes, the ice plug blocks the next thaw, and pressure splits the pipe or pops a fitting. Now the water is at your foundation where you can't see it.

What we do about it:

• Continuous pitch verified with a level, not eyeballed
• Discharge point kept clear of snow piles and plow windrows
• Pop-up emitters used sparingly, since lids freeze shut and vanish under snow
• On problem downspouts (north side, deep shade), a removable above-ground extension for winter

Can This Be Installed In January?

Above-ground work, yes. Trenching, usually not.

Once frost is a foot or more into the ground, a narrow trench becomes jackhammer work, spoil freezes into clumps you can't tamp back, sod won't knit, and PVC cement doesn't cure well in the cold. We'd rather not sell you a job that looks rough all spring.

So if you're standing in a wet basement in February, here's the sequence: we get long above-ground extensions and a clear winter path on it right away, clear the ice at the outlet, and schedule the buried work for the first real thaw. Cold-weather triage first, permanent fix when the ground cooperates.

Digging, Landscaping And Irrigation Lines

Before anyone digs, we call Diggers Hotline (Wisconsin's 811 locate service) and wait out the required locate period. Gas, electric, cable and water get marked, and we hand-dig near the flags.

Here's what homeowners don't always know: Diggers Hotline does not locate private lines. Irrigation laterals, invisible pet fence, low-voltage landscape lighting and that unpermitted line to the garage are all on the private side. If you have an irrigation system, tell us and share the as-built or zone map if you have one. We'll flag heads and probe by hand along the route.

If we nick a sprinkler lateral or a low-voltage wire on a route we chose, we repair it. That's on us, not you. What we can't take responsibility for is an unmarked private line we were never told about, so a two-minute conversation up front saves everybody money.

On the turf: trenches run narrow, usually 6 to 10 inches wide and 12 to 18 inches deep. We cut and set sod aside where we can, keep spoil on tarps, backfill, tamp, and put the turf back. Expect a visible seam for a few weeks. Same-day sod usually looks normal within a month; seeded areas knit in over one growing season. Crossing an established bed or under a walk takes more care, and we'll tell you up front exactly what has to be disturbed.

Permits, HOA Rules And Subdivision Drainage Plans

A buried downspout line that daylights on your own property generally does not require a permit in the City of Madison. Connecting to a storm lateral, working in a drainage easement, or cutting or boring under a public sidewalk or terrace does require approval. Towns and villages around Dane County set their own thresholds, so we confirm with the local building or engineering department before we dig, and if a permit is required we pull it.

Two more layers people forget:

Subdivision drainage plans. Most Dane County subdivisions built in the last 30 years have an approved grading and drainage plan on file with the municipality, and swales between lots are often platted drainage easements. You can't regrade or block one, and a new outlet that dumps into a neighbor's swale can put you crosswise with it.

HOA and architectural review. If you're in an association, visible changes can need approval: long above-ground extensions, a rain garden in the front yard, a new outlet or a dry well lid in a common sightline. Buried pipe under lawn is rarely an issue; anything you can see from the street might be. Check the covenants before we schedule, and we'll put drawings or specs in writing for your review committee.

Madison Rain Gardens And Stormwater Credits

Worth knowing: the City of Madison actively encourages downspout disconnection and rain gardens to keep roof runoff out of the storm system. Credit provisions do exist within the stormwater utility, but eligibility for a typical single-family home is limited, so don't count on a bill credit. Confirm current terms with the utility before you factor money into the decision.

UW-Extension in Dane County publishes solid rain garden guidance, including sizing based on roof area and soil type. If you have a spot 10 feet or more from the house that a swale can reach, a rain garden can be both the drainage fix and the prettiest option.

What If The Neighbor's Water Is Flooding My Yard?

First, talk to them. Most of the time it's an unaware homeowner with a splash block aimed at your side yard, and a $30 extension fixes it.

If that doesn't work, here's the lay of the land in Wisconsin. Courts here generally apply a reasonable use standard to surface water: you can manage water on your own lot, but you can't unreasonably concentrate and dump it onto someone else's. A downspout piped straight at a property line, or fill that reversed a platted swale, is the kind of thing that gets attention.

Practical steps, in order:

1. Document it. Photos and short videos during an actual rain, dated. Note where the water enters your lot.
2. Check the plat. Ask the city or village engineering department for the subdivision's approved grading and drainage plan. If a graded swale was supposed to carry water and someone filled it, you have something concrete to point to.
3. Call the municipality. Madison and most Dane County communities take drainage and grading complaints, especially if a plan on file was violated. Zoning and stormwater staff can inspect.
4. Protect your own side. A swale or berm on your property can redirect water, but don't wall off a drainage easement or push the problem to a third neighbor. That's how one dispute becomes two.
5. HOA, if you have one. Some associations enforce drainage covenants directly.

We can't give legal advice, but we can walk the property line with you and document elevations and flow paths in plain language, which is usually what the city or an attorney wants to see anyway.

Maintenance: What You're Signing Up For

Not much, but not zero.

• Clean gutters twice a year in Dane County: spring after the maple seeds and again after leaf drop, usually early-to-mid November. Oaks hold on, so a second pass helps.
• Flush buried lines once a year with a garden hose at the cleanout. Water should run steadily out the daylight outlet.
• Check the outlet each fall and after big snow so it isn't packed with leaves or buried by a plow.
• Signs of a plug: water backing out the top of the downspout, seepage at the elbow where it enters the ground, a dry outlet during a downpour, soggy turf or a dip along the pipe route.

If a line does plug, solid PVC with a cleanout snakes out in about an hour. That's the payoff for spending a bit more up front.

What NOT To Do

Don't tie into the footing drain or drain tile. That system exists to take water away from the wall. Feeding roof water into it pressurizes the exact zone you're trying to keep dry and overwhelms the sump.

Don't connect to the sanitary sewer. Prohibited in Madison and effectively everywhere in Wisconsin. Clear water overloads treatment during storms and can back sewage into basements.

Don't combine sump and downspout lines. Covered above. Separate systems, separate outlets.

Don't discharge onto a sidewalk, driveway or stairs. Ice liability, plus freeze-thaw spalls concrete.

Don't dump on the neighbor's lot. Concentrated runoff across a property line is a nuisance issue and often violates the subdivision drainage plan on file.

Is Any Of This Covered By Insurance?

Mostly no, and it's better to know that now. Standard Wisconsin homeowners policies exclude grading, drainage work and gradual seepage, so downspout extensions and buried lines are out-of-pocket maintenance and improvement. Some carriers sell a water backup or sump failure endorsement, which can pay for damage from a backup, but not for the drainage work itself. Read your endorsement or ask your agent.

What can be a claim is sudden storm damage: gutters torn loose by wind, downspouts crushed by hail or a limb, fascia damaged in a storm. That's different from a drainage problem that developed over ten years. If a storm is why you're on this page, say so when you call, and we'll document what's storm-related and what isn't. We meet adjusters on site all season for exactly that.

For a buried line in the $600-2,500 range, ask about payment options when we quote. We'll lay out financing on the estimate if spreading it out helps.

Talk To Someone Who's Dug Up A Lot Of Bad Flex Pipe

Water at the foundation rarely fixes itself, but it doesn't have to become a disaster either. Caught early, downspout drainage is one of the cheapest, highest-payoff repairs on a house. Left alone for years in clay soil, it turns into efflorescence on the block and a basement you stop using.

Buckshot Exteriors is family owned and has been working on Wisconsin homes since 1979, with crews out of Madison covering Dane County and the surrounding communities. Gutters and downspouts are part of the full exterior stack we handle along with roofing, siding, windows and storm restoration, and our gutter and drainage work carries a 5-year workmanship warranty printed on the estimate alongside manufacturer coverage on materials. Ask for our certificate of insurance and Wisconsin contractor credentials before work starts, we hand them over without being asked, and photos of local jobs are on our recent projects page.

The inspection is free, there's no obligation, and nobody is going to push you into a buried system if a $30 extension solves it. We'll walk the house with you in a light rain if that's what it takes, show you where the water is going, give you honest options with real numbers, and let you decide. Call the number at the top of this page or request your free inspection here.