French drains
A French drain gives groundwater an easier path than the soil around it. Here's when one makes sense in a Tallahassee yard.
A French drain is a trench lined with filter fabric, filled with washed stone and fitted with perforated pipe near the bottom. Water in the surrounding soil moves into the stone faster than it moves through the dirt, enters the pipe and runs downhill to an outlet. It's the right tool when the problem isn't just surface runoff but ground that stays saturated.
When is a French drain the answer?
- A low part of the yard that squishes underfoot for days after rain
- A hillside above the house that seeps water toward the foundation
- Wet ground at the base of a retaining wall or terraced bed
- A soggy strip that came back after the surface was already regraded
How do Red Hills soils change the design?
Many upland yards in north Tallahassee have sandy topsoil over a sandy clay loam subsoil. Rain soaks through the sand quickly, then slows at the clay and travels sideways along it. A drain placed across the slope, often called a curtain drain, intercepts that sideways flow before it reaches the house. The trench has to be deep enough to reach the wet layer, the fabric has to keep fine soil out of the stone, and the pipe needs steady fall all the way to a free outlet.
What about flat, sandy lots?
South of the Cody Scarp, around Woodville and parts of the south side, the land is flatter and sandier. Water often soaks in well, but there may be little fall to an outlet. A French drain still needs somewhere lower to go, so the contractor may combine a short drain with regrading or a swale rather than a long buried run.
Where does the pipe end?
Ask this first. Good outlets include a street gutter where the city or county allows it, an existing ditch or swale, or a pop-up emitter in part of your own yard that drains well. A pipe that simply ends in a sinkhole or a deep pit is not a plan: the City of Tallahassee's aquifer protection program says drainage wells are prohibited.
What should the written quote include?
- Trench route, length and depth
- Pipe type and diameter, fabric and stone
- Outlet location and how it's protected from clogging
- Who files the Sunshine 811 locate and how sod and beds will be restored
Every yard is priced on site. The contractor needs to see the slope, the soil and the outlet before putting a number on the job, so we don't quote prices here, and a figure given over the phone sight unseen is only a ballpark.
Where we connect you with help
- Tallahassee
- Bradfordville and Killearn Lakes
- Lake Jackson and northwest Tallahassee
- Woodville and south Leon County
Common questions
How long will a French drain keep working?
That depends mostly on keeping fine soil out of the stone and pipe. Filter fabric, clean stone and a cleanout let the drain be flushed instead of dug up later.
What's the difference between a French drain and a curtain drain?
A curtain drain is a French drain placed across a slope, uphill of the area you want to keep dry, so it catches water before it gets there.
Related services
- Downspout drain lines
- Regrading and swales
- Sump pumps and crawl space water
- Channel drains and dry wells
More background: Leon County drainage guide.
Yard turning into a pond after every summer storm?
Call and a local drainage contractor will come look at where the water starts and where it can safely go.