French Drain Installation Cost: Materials and Quote Planner

French drain installation cost starts with the system

A landscape French drain collects subsurface water and needs a feasible discharge route. A shallow yard trench, an uphill interceptor, a foundation drain and an interior basement system have different work scopes. Do not use a yard-trench materials budget as an interior waterproofing quote.

The calculator here estimates an exterior pipe-and-stone assembly that you specify. Foundation excavation, interior slab cutting, structural work, pump selection and electrical work require project-specific assessment. It does not determine trench slope, pipe capacity, foundation clearance or discharge permission.

Specify the stone section and filter assembly

Enter the dimensions actually occupied by stone, not the entire excavation if part of the trench contains soil or another layer. The calculation subtracts one circular pipe using its outside diameter. It rounds purchased pipe to your section length. Fittings, cleanouts, solid outlet runs and branches must be priced separately.

LSU AgCenter describes geotextile along the trench base and walls and emphasizes planning and maintenance. Soil and the chosen drain detail determine compatible filtration; this is not a rule that every sock, woven fabric or pipe assembly is unsuitable. LSU landscape French-drain guidance (external source).

Use the aggregate selection guide for product terminology, then confirm the drain specification. Dense-graded crusher run and clean drainage aggregate are different products; the crusher run planner serves a compactable-base ordering task, not filter design.

For a fully enclosed wrap, required width = twice section width + twice stone height + specified closure overlap. The top width is included. End returns and length-seam overlaps are separate. The tool requires a roll wide enough for one continuous wrap; joined narrower panels need a separate cutting layout.

A 50-foot example that reconciles

Use Try example for a fictional 50 ft run, a 12 in wide × 18 in stone-filled section and 4 in outside-diameter pipe. There is no stone allowance or bulk rounding. Fabric has a 12 in closure overlap, 1 ft return at each end, and a 6 × 100 ft roll; one roll is enough. The resulting net stone volume is 2.6162 yd³, wrap width is 6 ft and cut area is 312 sq ft.

These rates are invented to demonstrate the formula. A hypothetical installed rate of $20/ft would instead produce $1,000, plus the separate $30 outlet if it is outside that quote, for $1,030. Materials must not be added again. The installed quote must confirm whether its outlet is included.

Compare cost per foot and quote inclusions

French drain installation cost per linear foot = comparable quoted total ÷ covered drain length. A phone estimate cannot settle hidden obstructions, groundwater, access, utility conflicts or restoration. Ask for a drawing and dated work specification. There is no substantiated national installed-price average in this page.

• Excavation, disposal and access or hand-work constraints.
• Pipe specification, fittings, stone gradation and filter compatibility.
• Outlet location and permission, solid conveyance length, sump and electrical work where applicable.
• Restoration of paving, planting, lawn and interior finishes.
• Mobilization, minimums, tax, inspection and change-order conditions.

A Southern Nursery in Greenville, SC lists #57 gravel and crusher run at $40/ton, before separately described delivery. Confirm units, tax, minimums and suitability. Supplier listing (external source).

This is a material listing, not a drain installation quote. The planner uses stone prices per volume; request a matching yard price rather than entering a per-ton number in a per-yard field.

For bulk access and delivery questions use the delivery guide. Generic volume tools such as the gravel calculator do not automatically deduct drain pipes.

Plan the outlet before digging

Start by identifying the cause of standing water and whether grading, gutters or surface collection would address it. Drainage beside a driveway can be a separate line in the driveway cost budget; wet ground beside a shed should also be resolved before using the shed-pad planner.

Contact 811, follow the state ticket’s waiting requirements and confirm all utility responses before excavation. Private lines may need separate locating arrangements. Official before-you-dig instructions (external source).

Confirm local drainage permissions and avoid redirecting water onto neighboring property. Do not assume an outlet connection or sump can be selected from a price menu. Inspect and service the finished assembly according to its installer and product instructions; a fixed lifespan is not guaranteed.

Frequently asked questions