Should I bury my downspouts?

Burying them helps when the yard slopes toward the house, the basement gets damp, or surface extensions are in the way. Use solid pipe with a cleanout and a safe outlet.

What pipe is best for underground downspouts?

Smooth-wall solid PVC, usually 3-inch or 4-inch. It holds its slope and is easier to clear than corrugated pipe.

How deep should an underground downspout drain be?

Often around a foot in mild areas, deeper in cold climates. The key is a steady slope so the pipe drains fully between storms.

Can I connect downspouts to a French drain?

It is better not to. Roof water and grit can overload a French drain; run downspouts in their own solid pipe.

Guides

Underground Downspout Drainage: Burying Downspouts Right

Burying a downspout takes roof water away from the house without a pipe across the lawn. Done well, it protects the foundation for decades. Done badly, it becomes a clogged pipe that sends water straight back to the wall.

Updated 2026-10-26 · Gutter Fixing Editorial Team

An underground gutter drain is simply a pipe that collects water from the bottom of a downspout and carries it below ground to a safe place to discharge. That might be a pop-up emitter in the lawn, a dry well, a ditch, a rain garden or, where local rules allow, a storm drain. Homeowners choose buried drains to get rid of trip hazards and mowing obstacles, and because surface extensions often get moved, kicked or crushed and stop doing their job.

When burying downspouts makes sense

The yard slopes toward the house, so water from a short extension simply runs back.
There is a basement or crawlspace that gets damp after storms.
Downspouts drain onto paths, patios or driveways where water freezes or stains.
Surface extensions are in the way of mowing, play or foot traffic.
You want to carry water to a specific spot, such as a rain garden or the street.

The parts of an underground gutter drainage system

Part	What it does
Downspout adapter	Connects the rectangular or round downspout to round pipe
Catch basin	A box at the downspout base that traps debris and lets you clean out the line
Drain pipe	Usually 3-inch or 4-inch PVC or corrugated pipe, sloped away from the house
Cleanout	A capped access point for flushing or snaking the line
Outlet	A pop-up emitter, daylight outlet, dry well or connection to an approved drain

Gutter drain pipe: solid or corrugated?

Smooth-wall PVC pipe is the better choice for most downspout drains. Its smooth inside lets debris wash through, it holds its slope, and it can be cleaned with a snake or jetter. Corrugated flexible pipe is cheaper and easier to lay around curves, but its ridged inside traps sediment and leaves, and it can sag or be crushed in the trench. Many clogged underground downspouts are corrugated pipe that has filled with silt.

Perforated pipe, with holes along its length, is meant to collect or disperse groundwater, as in a French drain. It is the wrong pipe for carrying roof water away from a foundation, because it lets water out right where you do not want it. Use solid pipe from the downspout until the water is well away from the house.

Slope and depth

The pipe needs a steady fall all the way to the outlet, commonly at least an eighth to a quarter inch per foot. Low spots hold water and silt and freeze in winter. Depth depends on the frost line and what will pass over the pipe; in many areas a shallow trench of around 12 inches is enough, while cold regions may need more or a design that drains fully between storms. Call 811 before digging so buried utilities are marked.

Where to send the water

Pop-up emitter: a cap at the end of the pipe that lifts when water arrives and closes when it stops. Simple and common for lawns.
Daylight outlet: the pipe exits on a slope lower than the house, often with a rock splash pad.
Dry well: a buried chamber or gravel pit that lets water soak into the soil. Needs soil that drains.
Rain garden: a planted low area that absorbs runoff.
Storm sewer or curb: only where the local authority allows it; many cities restrict roof water connections.

Keep outlets at least ten feet from the foundation where possible, and never send water onto a neighbor's property.

Downspout catch basins and cleanouts

A downspout catch basin at the base of the pipe gives debris somewhere to settle before it enters the buried line. It usually has a grate that lifts off for cleaning. A cleanout, either at the basin or a separate capped riser, lets you push a hose or drain snake down the line. Without one, clearing a blocked buried drain may mean digging it up. The clogged downspout guide covers how to clear a line that has stopped draining.

French drains and downspouts

A French drain is a gravel-filled trench with a perforated pipe that collects groundwater and surface water from soggy ground. It is a different job from a downspout drain. Connecting downspouts into a French drain can overload it during storms and fill it with roof grit. If you need both, run the downspout in its own solid pipe, or join them only well downstream where the French drain is sized for the extra water.

Common mistakes

Using perforated or corrugated pipe for the whole run.
No catch basin or cleanout, so a clog means digging.
Pipe laid flat or with dips, which hold silt and freeze.
Outlets too close to the house or aimed at a neighbor.
No gutter guard or leaf trap above, so leaves wash straight into the pipe.
Joining several large roofs into one small pipe.

DIY or professional?

A single downspout drain across an open lawn is a reasonable weekend project for someone comfortable with a shovel and a level. Long runs, multiple downspouts tied together, rocky ground, and connections to dry wells or storm drains are better left to a contractor with trenching equipment. Contractors in our network who install downspouts can design and lay buried lines, add catch basins and cleanouts, and connect them to your existing downspouts. The downspout and drainage section of the pricing hub gives cost ranges.

Looking after a buried drain

Once a year, run a hose into each downspout at full flow and check that water appears at the outlet quickly and strongly. Lift catch basin grates and scoop out sediment. If the pop-up emitter stays wet and soggy long after rain, the line may be partly blocked or the outlet may sit in a low spot. Keeping the gutters above clean is the single best way to keep buried pipes clear.

Running a downspout under a sidewalk, driveway or walkway

Burying a downspout under a sidewalk is one of the most common requests, because a pipe across a path is a trip hazard and an ice patch in winter. A downspout drain under a sidewalk or walkway is usually a solid 3-inch or 4-inch pipe bored or tunneled beneath the slab, so the concrete does not have to be broken out. A downspout under a driveway needs a deeper, stronger pipe, often schedule 40 PVC, so vehicle loads do not crush it. Where boring is not possible, a low channel drain with a grate can carry water across the surface instead.

Downspouts connected to sump pumps, French drains and sewers

A sump pump discharge line should not be connected to a downspout. The downspout pipe is not built for pump pressure, and in a storm both send water at once, which can back up the line. Run the sump pump to its own outlet well away from the house. A downspout connected to a French drain is also a problem in most cases: the French drain is meant to collect groundwater, and roof water can flood it. Where a French drain is attached to a downspout, use a solid pipe through it or separate the two.

Some older homes have a gutter downspout connected to the sewer or storm sewer. Many cities now restrict or ban this and offer disconnection programs, so check local rules before relying on it. A downspout leach field, sending roof water into a septic drain field, should be avoided because it overloads the system.

Where the buried pipe ends: dispersers, pop-ups and river rock

A downspout pop up emitter at the end of the pipe lifts when water arrives and drops flat when dry. A downspout disperser or drain water disperser spreads the flow across a wider area. A catch basin under a downspout traps debris before it enters the pipe. At the surface, downspout drainage with river rock or a dry creek bed slows water and looks natural. Downspout drain tile installation, using perforated pipe in a gravel trench, lets water soak in along the way where the soil allows it.

Choosing pipe and fittings

Corrugated plastic downspout pipe is cheap and flexible, and attaching corrugated pipe to a downspout takes a simple adapter, but its ridges trap silt. Smooth PVC drains faster and is easier to clean. A 6 inch gutter drain pipe is used where two or more downspouts join, or on large roofs. Flex gutter drain pipe suits short above-ground runs rather than buried lines.

Gutter drainage solutions and ideas

Underground downspout drainage ideas range from simple to involved. The simplest gutter drainage solutions are longer extensions and splash blocks. Next come automatic drain-away downspout extender systems that roll out when it rains. Extending gutters underground to a pop-up emitter, a dry well or the street is the most permanent of the rain gutter drainage solutions. Diverting downspouts away from the house is the aim in every case. Where a gutter is coming away from the house, fix that first, because no drain helps if water misses the gutter.