French drain INSTALLATION COST

Downspout drainage

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Manage roof water before it saturates the ground beside the house. Compare an accessible surface extension with a separate solid underground pipe.

US house and yard cutaway showing the drainage systems outside the house.

Where should downspout drainage go?

Manage roof water before it saturates the ground beside the house. Compare an accessible surface extension with a separate solid underground pipe.

Keep the roof-water route distinct

Check that gutters and downspouts are clear and connected before planning a buried system. Concentrated roof water belongs in a route designed to carry it away. PNNL’s guidance keeps roof drainage separate from foundation drains; the perforated collection section beside a footing should not become a roof-water distribution pipe.

Choose a destination that works

A surface extension needs a receiving grade that carries water onward without erosion or a walkway hazard. Underground pipe needs a functioning discharge point and service access. PNNL describes program guidance using at least 5 feet to sloping final grade or an underground catchment at least 10 feet away; those are not universal local-code approvals.

Measure each downspout and run

Count the downspouts being connected and measure the actual pipe routes. A per-downspout package and a per-foot pipe allowance can describe overlapping work. Our calculator compares the two bases and uses the larger allowance rather than adding both for the same scope.

Special crossings or discharge construction may still need separate pricing.

Inspect after storms

Look for overflowing gutters, leaking joints, backed-up inlets and erosion at the outlet. Surface extensions are easy to inspect but can be displaced. Buried runs keep the lawn clear but conceal blockages.

Agree how the installer will provide cleaning access and preserve the outlet elevation.

Cutaway of a yard French drain trench beside a brick ranch house: fabric-lined trench, gravel and a black perforated pipe under the lawn.
A yard drain in cross-section; outlet suitability needs an on-site check.

Nonwoven fabric keeps soil out of the gravel so the drain doesn't clog.

Washed gravel around the pipe lets water reach it from every side.

Water rises into the holes and runs along the pipe, which slopes toward the outlet.
Questions to ask before work starts
Should I use perforated pipe from the downspout?
Use an appropriate solid conveyance route for concentrated roof runoff. Collection pipe and roof-water transport serve different functions.
Is a pop-up emitter always sufficient?
No. It must suit the elevations and expected flow, remain serviceable and discharge to an acceptable location.
Sources
Cutaway of a yard French drain trench beside a brick ranch house: fabric-lined trench, gravel and a black perforated pipe under the lawn.

French drain cost

Per-foot prices, worked examples and what changes the total.

US house and yard cut away to show a French drain, downspout line, dry well, catch basin and driveway channel drain.

French drain installation, step by step

What a pro does, from the site check to lawn repair.

Two-story US house with a gravel French drain trench curving through a wet lawn.

French drain for a soggy yard

When a yard drain fixes standing water, and when it won't.