French Drain Cost: Average Prices & Cost Factors

A French drain is a gravel-filled trench with a perforated pipe that collects groundwater and carries it away from a foundation, yard, or low spot. It solves a specific problem: water that pools or seeps because the ground cannot drain fast enough. The price depends mostly on how long the trench is, how deep it goes, and what stands in the way.

The tables below come from published guides with a check date of Oct 11, 2026. Cost per linear foot is the figure most contractors use to build a quote, so it appears first.

Exterior curtain drains are the simplest and cheapest. They run in a shallow trench across a yard to redirect surface and shallow groundwater. Perimeter drains, sometimes called weeping tile, circle the foundation at footing depth, which means deeper digging and more labor. Interior drains are cut into the basement floor or installed in a crawl space, and they cost more per foot because the work involves breaking concrete and working in tight spaces.

If you know the length, multiply it by the per-foot range for your drain type to get a rough budget. A contractor's quote should add the items below.

Drain work often comes with extra items. Sump pump installation is the most common, since interior drains usually empty into a sump pit. Permits are required in many places. Cleaning is a maintenance cost that applies to older systems.

Published guides disagree because they describe different drains. One source covers outdoor installs only, while another includes basement and crawl space systems that cost more per foot. Soil type, access, and local labor rates also play a part.

• Length. Cost scales with the number of linear feet.
• Depth. Perimeter and interior drains go deeper than yard drains.
• Soil. Rocky or clay soil is slower to dig than loose soil.
• Access. Fences, trees, patios, and landscaping make digging harder or require restoration afterward.
• Drain location. Interior drains require cutting and patching concrete.
• Discharge point. Draining to daylight is simple. Pumping water out through a sump costs more.
• Permits and inspections. Local rules vary, and some areas require a permit for drainage work.

Exterior drains work well when water collects in a yard or flows toward the house. They require digging next to the foundation and restoring landscaping. Interior drains are chosen when water seeps through basement walls or floors and exterior access is limited. They can leave the yard alone, but they involve breaking the floor and usually come with a sump pump.

Neither type fixes a structural crack or a failed downspout by itself. Look at gutters, grading, and downspout extensions first, since fixing those is often cheaper than trenching.

A shallow curtain drain in an open yard is within reach for a capable homeowner. The work is mostly digging, but slope matters, because the pipe needs to fall consistently toward the outlet. Before digging, call 811 to have underground utilities marked.

Hire a professional for foundation-depth or interior drains. Digging beside a foundation can undermine it if done wrong, and interior work involves concrete cutting and sump systems. A mistake can leave you with a drain that does not work and a repair bill on top of it.

Drains can clog with silt, roots, or debris over time. A cleaning service flushes the pipe and checks the outlet. Keep the discharge point clear and watch for standing water that returns, which may signal a blockage.

• Is the quote priced per linear foot, and what total length does it assume?
• Does it include a sump pump, permit, and restoring landscaping or flooring?
• Where will the water discharge, and is that allowed on my property?
• What pipe, gravel, and fabric will be used?
• Is there a warranty on the drainage system?

Standing water in the yard days after rain, damp basement walls, soggy soil near the foundation, and water flowing toward the house are common reasons people consider one. A drainage contractor can walk the property, check the grading and gutters, and say whether a drain, a regrade, or both fit the problem before you commit to trenching. Get the diagnosis in writing so you can compare quotes for the same scope.