French Drain Cost

French drain cost depends first on which system solves the water problem: an exterior yard drain and an interior basement system are different jobs. Angi’s May 2026 guide gives $10-$50 per linear foot for exterior systems and $40-$100 for interior systems.* Measure the complete collection and discharge route, then get an itemized quote. A stone-only subtotal is not an installed drainage budget.¹

National French drain cost references*

Sources: Angi¹, Bob Vila² and GoodGravel³.

*National average cost references from named publishers, not an independent MeasureScout survey or guaranteed local quotes. The two whole-project averages differ by source/date and must not be blended. The per-foot figures are published ranges; stone prices are medians of listings, not national averages. GoodGravel’s 1,445 listings span 73 sites in 25 states and lean toward landscape supply yards. Confirm current product, delivery, tax and installed scope.

Diagnose the drainage job before comparing prices

NDS separates surface runoff from subsurface water and advises identifying a safe discharge point and starting design from that discharge point or retention basin. Soil, elevations and the route affect the system. Its French drain overview identifies pipe, aggregate, fabric, couplers and end caps as cost components, with permits, equipment and labor also possible.⁴, ⁵

• Define where the water comes from, where it collects and what must be protected. A wet basement does not by itself prove that a shallow yard French drain is the right repair.
• Have the route, elevations, outlet and local discharge requirements checked. Do not assume you can drain onto a neighbor’s property or into a street/sewer.
• Separate perforated collection length from any solid discharge-pipe length, connections, cleanouts, outlet protection and pump system.
• Near foundations, deep excavations or persistent basement water, get qualified site-specific assessment. This page does not approve excavation depth, structural clearance or drainage capacity.

Measure the aggregate envelope, not every inch of excavation

Gross stone-envelope cu ft = length (ft) × stone-envelope width (in) × stone-envelope height (in) ÷ 144. The aggregate envelope is the part actually filled with stone, not necessarily the entire trench including soil/sod restoration. Split changing sections into measured segments.

Pipe displacement cu ft = π × [actual outside diameter (in) ÷ 24]² × length within the envelope (ft).
Net stone yards = (gross envelope cu ft − displaced pipe/other known volume) ÷ 27. Use the measured outside envelope diameter, not a nominal pipe label. Do not subtract ordinary voids between stones again; bulk aggregate is already a bulk-volume measure.

Our geometric displacement formula assumes a round cylindrical outside envelope fully inside the stone zone. Corrugations, fittings and prewrapped systems need their actual dimensions or manufacturer quantity method. Do not infer how much a fabric sheet displaces or subtract a made-up fabric volume. Keep net geometry, chosen handling allowance and supplier sales increments separate.

The 4.5-in outside diameter is a hypothetical measured input, not the outside diameter of every nominal 4-in product. Dimensions here illustrate arithmetic, not drain design. Use the French drain calculator only with settings that match your stone envelope and displacement assumptions.

Three checked cost examples

All unit prices, allowances, sales increments and bid exclusions below are invented local quote inputs. They are not asserted market averages. Tax and any unlisted work are excluded.

Example 1: stone cost for a selected 50-foot section

For the 50 × 1 × 1 ft stone envelope above, gross volume is 50 cu ft. A selected 4.5-in outside pipe envelope displaces 5.522331 cu ft, leaving 44.477669 cu ft / 1.647321 yd³. A chosen 10% handling allowance gives 1.812053 yd³. Hypothetical half-yard order increments make the purchase 2 yd³.

At a hypothetical $55/yd³ plus $80 delivery, stone/delivery is $190. Pipe, fabric, fittings, outlet, excavation, spoil disposal, installation and restoration are not included. Pricing the old whole-trench rounded 2.04 yd³ at a yard rate did not represent this actual billable order.

Example 2: compare exterior and interior scopes

For a selected 50-ft installation, Angi’s exterior $10-$50/ft band gives $500-$2,500; its interior $40-$100/ft band gives $2,000-$5,000. These are separate source-based budget calculations, not bids for the same job or guarantees that a contractor will accept the low-end amount.¹

Ask whether excavation, concrete cutting/replacement, disposal, fabric, pipe, aggregate, pump/electrical work where needed, discharge connection and restoration are included. Do not add the $190 material example to an installed quote that already includes that material.

Example 3: higher per-foot bid, lower comparable total

For a 100-ft system, hypothetical Bid A is $28/ft with restoration and a discharge connection excluded: $2,800, plus $900 restoration and $450 discharge work = $4,150. Hypothetical Bid B is $39/ft including the same system, restoration and discharge work: $3,900. It is $250 less for the stated matching scope despite the higher headline rate. This does not prove either system is correctly designed; specifications must match before cost comparisons count.

Build the rest of the material budget

• Pipe: include perforated collection and solid discharge runs as designed. Buy actual usable lengths, fittings and connections, not just the trench length.
• Fabric: confirm specified filter material, wrap width, overlap, end coverage and roll dimensions. Length alone does not determine enough wrap coverage.
• Aggregate: confirm clean drainage material/gradation appropriate to the design, sales unit, density basis if ton-priced, minimum order and delivery. A washed-gravel price category does not certify that product.
• Other components: cleanouts, catch basins if designed, outlet hardware, pump/basin/control or electrical work if needed.
• Construction/restoration: equipment, safe excavation, spoil hauling, hardscape replacement, soil/sod/landscaping and cleanup.

NDS also describes prewrapped aggregate-and-mesh pipe systems. Their quantity and installation method are not the same as a traditional gravel-filled envelope, so do not price them by adding a full conventional stone order without checking the exact system.⁴

Before digging in the U.S.

Contact 811 or your state 811 center before any digging, wait the required response period, confirm that all utilities have responded and follow safe-digging rules around the marks. Check with the contractor who is handling the ticket. Local permits, private-line locating and discharge approval are separate project checks, not established by a cost calculator.⁶

French drain cost FAQ

Why does one guide say $5,000 and another $9,250?

Bob Vila’s $5,000 is from its June 2024 article attributed to Angi/HomeAdvisor; Angi’s own May 2026 page says $9,250. Their dates, samples and mixes of systems differ. Neither is a bid for your measured route.¹, ²

How much does a 50-foot French drain cost?

Angi’s published exterior band produces $500-$2,500 for 50 ft; its interior band produces $2,000-$5,000. Outlet, access and restoration can change the total. Ask for a quote describing the actual system rather than applying a blended per-foot rate.¹

Can I estimate gravel from full trench volume?

Only if that entire measured volume is the stone zone. Subtract known pipe displacement on an actual outside-dimension basis, account for non-stone cover separately, then resolve allowance and supplier increments. Do not call excavation volume stone demand without checking the section.

Does fabric cost just equal drain length times price per foot?

Only if the quoted product width and overlap already fit the specified wrap. Confirm coverage in both dimensions and whole rolls, plus ends and joins.

Is a cheap French drain the right fix for every wet yard?

No. NDS’s drainage guidance distinguishes surface and subsurface problems and stresses soil, topography and safe discharge. Determine the needed system before comparing prices.⁵

Related drainage guides

• French drain calculator
• Stone quantity for a French drain
• French drain depth and outlet planning
• Drainage stone size and type
• Sump pump installation cost

Sources

1. Angi: French Drain Cost (updated May 30, 2026; national consumer cost guide)
2. Bob Vila: French Drain Cost (June 27, 2024; older figures attributed to Angi and HomeAdvisor)
3. GoodGravel: Gravel Prices by State (October 2026; material-only published-listing medians)
4. NDS: French Drain Installation Guide (manufacturer overview; components, outlet and installation scope)
5. NDS: Principles of Exterior Drainage, Quick Review (2007; manufacturer drainage assessment and safe-discharge guidance)
6. 811: Before You Dig (U.S. utility marking, response and safe-digging process)

Estimates only. This is cost and quantity planning, not drainage engineering or permission to excavate. Confirm the design, discharge rules, utilities and current quote with qualified local help.

Guide: Best gravel for a French drain: size and type