If you’ve watched water pool in your yard after a Middle Tennessee rainstorm, you’ve probably asked the same question every homeowner around here asks:
“What’s this actually going to cost me to fix?”
I’m Troy Galletly, owner of Excavation Contractors LLC. We install French drains across Franklin, Brentwood, Spring Hill, and the rest of Williamson County. After hundreds of properties in this area, I’m going to tell you straight what a French drain costs here in 2026 — no vague “it depends,” no national-average numbers that have nothing to do with our clay.
Let’s get into it.
Quick answer: what does a French drain cost in Williamson County?
| Project type | Typical 2026 price range |
|---|---|
| Small / single problem area (50–75 ft, simple layout) | $1,500 – $2,000 |
| Standard residential French drain (75–150 ft, average yard) | $2,500 – $4,000 |
| Larger property or complex layout (150–250 ft, slope or obstacles) | $4,500 – $7,500 |
Most Franklin and Brentwood homeowners we work with land in the $2,500 – $4,000 range for a standard yard drainage fix.
Your number depends on your property — how much pipe, how deep, what we hit in the ground, and where the water goes once we catch it. More on that below.
Why French drains cost more in Williamson County than the national average
If you’ve Googled “French drain cost,” you’ve probably seen national averages around $1,500–$2,500. Here’s why our pricing runs higher than that:
1. We’re digging through clay, not soil.
The Nashville Basin sits on dense red and gray clay over limestone bedrock. That clay holds water for days instead of letting it soak through — which is the whole reason your yard floods in the first place. Trenching clay is harder, slower, and tougher on equipment than the loose, loamy soil most national price guides assume.
2. Limestone surprises.
A lot of yards in Brentwood and Franklin have limestone within 12–24 inches of the surface. When we hit it, we sometimes need a rock saw or breaker to get through. That’s labor and equipment time that moves the price.
3. Mature tree roots.
Especially in Brentwood, older properties have big oaks, maples, and hackberries. Their roots make trenching slower and take careful planning so we don’t kill the tree getting the drain in.
4. Williamson County permits and HOA paperwork.
Larger projects can trip Franklin’s grading ordinance or Nashville Metro’s grading permit thresholds (10,000 sq ft of disturbance or 100 cubic yards of earth). Plenty of Brentwood HOAs also require ARC approval before any work starts. We handle that paperwork for you — but it’s real work that affects the timeline and the price.
What changes your specific price (the 7 factors)
When we quote your job, here’s what we’re actually measuring:
- Linear footage of pipe — the single biggest cost driver
- Trench depth — deeper runs for downhill grades or basement-level drainage cost more
- Where the water goes — daylighting to a swale is cheapest; a pop-up emitter, dry well, or sump connection costs more
- Soil and rock — straight clay is standard; limestone or a root mass adds time
- Obstacles — sidewalks, driveways, irrigation lines, gas lines, mature trees, fences
- Restoration — sod replacement, mulch beds, regrading the surface back smooth
- Permits and HOA paperwork — Franklin, Brentwood ARC, Spring Hill, and Nashville Metro each want something different
When a French drain is the right fix (and when it isn’t)
A French drain is the right call when:
- Water pools in low spots for more than 24 hours after rain
- Your downspouts dump at the foundation and the ground near the house stays soggy
- A neighbor’s yard drains into yours (we see this constantly in the high-density Spring Hill subdivisions)
- You’ve got a wet basement or crawl space from saturated clay pushing against the foundation
- Surface water is carving erosion channels or killing grass in certain zones
A French drain is not the right fix — or not the only fix — when:
- The real problem is bad grading. Sometimes regrading is cheaper and solves it without buried pipe.
- You’ve got a high water table. That needs a sump and discharge system, not just a drain.
- Your gutters and downspouts are the source. Extending downspouts might fix 80% of it for a couple hundred bucks instead of a couple thousand.
This is exactly why we do a free on-site assessment before we quote. About 1 in 5 properties we look at don’t actually need a full French drain — and we’ll tell you that to your face instead of selling you one anyway.
Why grading and drainage have to be done together here
This is the part most homeowners — and honestly some contractors — miss. Our clay swells when it’s wet and shrinks when it’s dry. That constant movement, plus poor original grading, is why yards in this area develop drainage problems years after the house was built. It’s especially bad on newer construction in Spring Hill, where the national builders rush the final grade and move on.
A French drain catches water. Grading directs water. You need both working together, or the drain eventually gets overwhelmed.
The Excavation Contractors LLC process
- Free on-site assessment — we walk your property, find the actual problem (not just the symptom), and explain what we’d do
- Written fixed-price quote — no “time and materials” surprises
- Permit and HOA paperwork — we handle Franklin, Brentwood ARC, Spring Hill, and Nashville Metro requirements
- Installation — most residential French drains take 1–3 days
- Final walk-through and cleanup — sod or mulch restoration is in your quote
- Workmanship warranty — we go over it when we quote
Ready to get a real number for your property?
The ranges on this page will get you in the ballpark, but the only way to know exactly what your project costs is for us to come see it. We offer free on-site French drain assessments in Franklin, Brentwood, Spring Hill, Thompson’s Station, Nolensville, and the rest of Williamson County.
In June we typically have openings within 5–10 business days. Once mid-summer storms roll through, that calendar fills up fast.
Need help fixing drainage, grading, or runoff on your property?
Frequently Asked Questions
How long does a French drain take to install?
Most residential French drain installs in Williamson County take 1–3 days, depending on footage, depth, and whether we hit rock or roots.
Do I need a permit for a French drain in Franklin or Brentwood?
Most residential French drain work falls below the Nashville Metro grading permit threshold (10,000 sq ft of disturbance or 100 cubic yards of earth movement). Brentwood HOA communities often require ARC approval — we handle that for you.
Will a French drain tear up my lawn?
We trench, lay pipe and gravel, then restore the surface with topsoil and sod (or mulch in beds). The trench line shows for a few weeks while grass re-establishes, then it disappears.
How long does a French drain last?
A properly installed French drain in our clay typically lasts 15–25+ years. The most common failure is tree roots getting into the pipe — which is why we use modern perforated pipe and filter fabric built to resist roots.
Can you fix a French drain that’s already failing?
Yes. We diagnose existing drains, find the failure point (usually a crushed section, root infiltration, or a clogged outlet), and repair or replace as needed. Repairs typically run $500–$1,500; a full replacement falls in the ranges above.
Do you offer financing?
Yes — we offer financing options to help spread the cost of larger drainage and grading projects. We’ll walk you through what’s available during your free on-site assessment so you can pick what works for your budget.
What areas do you serve?
Franklin, Brentwood, Spring Hill, Thompson’s Station, Nolensville, College Grove, Cool Springs, and the surrounding Williamson County and southern Davidson County areas.
