Cost and process
French drain installation in Marietta, GA
A French drain is a fabric lined trench of washed stone around a perforated pipe that carries water out of a soggy yard to a downhill outlet. In Marietta and across Cobb County, installed French drains typically run about $20 to $50 per linear foot, and most projects land between $2,000 and $7,000. A local crew plans the outlet first, then gives you a written price.
Right fix?
When a French drain is the answer, and when it is not
Marietta sits on Georgia Piedmont clay and gets about 50 inches of rain a year. Clay drains slowly, so water that soaks in has nowhere to go. A French drain fixes water moving through the soil. Water running across the top of the ground, or pouring out of a downspout, often has a cheaper fix.
Good fit: ground that stays wet
A lawn that is soggy for days after rain, a wet strip along the bottom of a slope, or water seeping toward a crawlspace.
Maybe: water running across the surface
A low spot that ponds during the storm usually needs a catch basin or a swale. Many yards get both. See catch basins and dry wells.
Check first: downspouts and grading
If the water comes off the roof or the yard tilts toward the house, underground downspout lines or regrading may solve it for less.
Process
How a French drain is installed
The steps are simple. Doing each one properly in clay is what makes the drain last.
Find the water and the outlet
Where the water collects, where it comes from, and where it can legally leave the lot: a daylight outlet downhill, a pop up emitter, a dry well, or the street where the city allows it. No outlet, no trench.
Mark utilities
Georgia 811 is contacted before digging so gas, power, water and cable lines are marked. Irrigation lines and invisible fence wires get found and flagged too.
Dig with a steady fall
A trench about a foot wide, usually 18 to 24 inches deep for a yard drain, sloped downhill the whole way to the outlet. Low spots in the trench hold water and silt.
Fabric, stone and pipe
Filter fabric lines the trench, washed stone goes in, the perforated pipe is set on the stone, and more stone covers it. The fabric folds over the top so clay cannot wash in.
Cleanout and outlet
A cleanout where the run turns or starts, and a finished outlet that will not wash out the ground below it.
Cover and restore
Stone left exposed, or soil and sod put back. Extra soil is hauled off or used to fix grading.
Typical prices
French drain installation cost in Marietta
Typical installed ranges from Angi's 2026 data, not our quotes. Most French drains are priced by the linear foot, then adjusted for the job.
$2,000 to $5,000
Deep footing drains, long runs to an outlet and restoring hardscape cost more.
- French drainPer linear foot, installed$20 to $50 / ft
- Typical French drain projectMost homeowners$2,000 to $7,000
- Trench drainDriveways and patios$30 to $70 / ft
- Catch basinOften paired with a French drain$600 to $2,000
- Dry wellWhere there is no downhill outlet$1,000 to $4,000
Source: Angi yard drainage cost (2026). Typical ranges, not quotes.
What moves the price
- Depth: footing drains along a foundation cost more than shallow yard drains
- Distance from the wet area to a usable outlet
- Access: fenced backyards and steep lots may mean hand digging
- Tree roots, buried rock and existing lines in the way
- Putting back sod, pavers, mulch beds or concrete
Cobb County yards
Where French drains go in around Marietta
On sloped lots near Kennesaw Mountain and out toward Dallas Highway, water soaks into the hill and comes out at the bottom of the yard, so a drain across the base of the slope catches it before the lawn turns to mud. In graded subdivisions in Kennesaw, Powder Springs and Acworth, the original swales often fill in over the years, and a French drain or a regraded swale puts the water back on its path. On small Smyrna infill lots, drains often run along the property line below a newer, higher lot next door. On wooded East Cobb lots, shade and roots keep the clay wet, and drains often run along the uphill side of a patio or driveway.
A French drain is also part of every properly built retaining wall: a perforated pipe in gravel behind the bottom course. If an existing wall is bulging or seeping, see retaining wall repair. If soil is washing off a slope, see erosion control. For catch basins, downspouts and grading, see the yard drainage overview.
Water should leave your property without being aimed at a neighbor's yard. A good plan sends it to an outlet on your own lot, a dry well, or an approved point.
FAQ
French drain installation questions
How much does French drain installation cost in Marietta?
Angi's 2026 data puts French drains at about $20 to $50 per linear foot installed, with most projects between $2,000 and $7,000. Depth, the distance to a usable outlet, digging access and putting sod or pavers back are what move the price. Your written quote after a site visit is the real number.
How long does it take to install a French drain?
Many yard drains are dug, filled and covered in a day or two once utilities are marked. Long runs, deep footing drains, tight backyard access or a wet week can stretch that. Your quote states the expected time on site.
How deep should a French drain be in clay soil?
Yard French drains are usually about 18 to 24 inches deep and about a foot wide. Footing drains that protect a foundation or crawlspace go deeper. In red clay, the depth matters less than a steady fall to the outlet and fabric that keeps the clay out of the stone.
Do I need a permit for a French drain in Cobb County?
A simple yard drain on your own lot usually does not need a building permit. Tying into a street or storm system, working near a creek or lake, or moving a lot of soil can need approval from the city or Cobb County. That is checked for your address before work starts.
Will a French drain clog in Georgia red clay?
It can if it is built without filter fabric or with dirty stone. Wrapping washed stone in fabric, using clean pipe and adding a cleanout where the run changes direction keep it working for years. A drain that dumps into a low spot with no outlet will also stop working, which is why the outlet comes first.
Get a free French drain quote
Tell us where the water sits and where it comes from. A photo after a rain helps. A local crew follows up with a written plan and price.