The short answer: Modernize’s cost guide puts an outdoor french drain at $10 to $65 per linear foot, or roughly $1,000 to $6,500 for a 100-foot drain. Angi’s 2026 guide puts total installed cost at $500 to $18,000 (national average $9,250), with exterior yard drains typically $10 to $50 per linear foot and interior basement systems several times higher. The guides don’t all agree with each other - even Angi’s own page gives a wider range in its summary box than in its article body - so treat all of these as national indicative ranges, not verified Detroit quotes. The installer sets the real price after seeing your yard.
What actually drives the price
- Length of the drain. Most of the cost is per foot: digging, gravel, pipe, fabric, restoration.
- Depth. Published guides put a standard yard drain at 18 to 24 inches deep; foundation-depth work is a different job with different pricing.
- Soil. Detroit-area clay-rich soil is heavy digging, and rocky or root-filled ground slows the crew.
- The outlet. If there’s no easy downhill discharge point, the job may need a dry well or a longer run - sometimes the biggest variable in the quote.
- What’s in the way. Fences, patios, driveways, sprinkler lines and mature trees add time.
- Restoration. Seed-and-straw is standard; sod or landscaping rebuild costs more.
Why quotes differ
Published installation guides treat a fabric-lined trench, washed stone and a real outlet as standard practice. Two quotes can differ simply because one includes that spec and the other doesn’t - or because one includes restoration and the other doesn’t. Comparing quotes line by line tells you more than comparing totals.
How to get a real number
Three quotes from people who have walked the yard beat ten phone estimates. Each quote should name the footage, depth, pipe and fabric, the outlet, and what restoration is included. If one is far off the others, ask why - the answer teaches you something either way.
The one number nobody can give you online
Yours. Soil, slope, access and outlet decide it. Send the form and we’ll try to match your job with a local drainage professional who can quote your yard. We are a referral service - we may be paid for referrals.