French drain INSTALLATION COST

Foundation drainage outside the house

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Separate roof runoff, surface grading and exterior footing drainage. They manage different parts of the water path around a home.

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

How does foundation drainage work outside the house?

Separate roof runoff, surface grading and exterior footing drainage. They manage different parts of the water path around a home.

Start above the footing

Inspect gutter discharge and grade around the house before assuming the footing pipe must be replaced. PNNL explains how exterior water management reduces soil saturation near foundations. A yard collector, a downspout pipe and an exterior footing drain can all be relevant, but their routes and connections should be evaluated separately.

Identify the actual exterior drain scope

An exterior footing drain collects water near the foundation base. Reaching it can involve deep excavation, restricted access and protection of the structure and utilities. That is different from a shallow yard trench.

Ask the contractor to identify depth, wall length, existing pipe condition and the method of safely carrying out the work.

Keep waterproofing work separate

Drain pipe conveys water; a wall membrane addresses water entry through an exterior wall assembly. Interior perimeter systems and sump work are separate topics at waterproofingcost.com. A proposal should name each scope so you can see what is included, what is excluded and which specialist is responsible.

Require investigation before excavation

Request evidence for the diagnosis, a confirmed outlet and an excavation plan appropriate to the property. Do not use the conceptual illustration as digging guidance. The published exterior pipe range below excludes wall waterproofing and structural repair.

Foundation access and restoration can make the complete project substantially different.

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
Does replacing the pipe stop every basement leak?
No. Water entry can involve wall defects, joints, grading and other sources. Have the cause assessed and the proposed remedy explained.
Can roof water feed the footing drain?
PNNL’s roof-drainage guidance keeps the systems separate. Ask the designer to show how concentrated runoff is carried away without loading the foundation collection system.
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.