French drains in Mobile, Alabama
In Mobile, a French drain is only as good as the place it empties. Here's how they work and when they're the right fix.
A French drain is a trench wrapped in filter fabric, filled with washed stone and fitted with a perforated pipe near the bottom. Water in saturated soil moves into the stone faster than it moves through the surrounding ground, drops into the pipe and flows downhill to an outlet. It's built for ground that stays wet, not just for water flowing across the surface.
When does a French drain make sense?
- A low part of the lawn that still squishes underfoot two days after a storm
- A narrow side yard where water collects between two houses
- Seepage along a slab edge, patio or paver walk
- Wet ground at the foot of a slope, berm or low retaining wall
Why does the soil matter so much here?
Many Mobile-area soils have a sandy or loamy top layer over slower clay subsoil. The Malbis series, a common Southern Coastal Plain soil described from Baldwin County, has moderately slow permeability in its lower subsoil, plinthite nodules and a perched water table each year from late fall through early spring. Rain soaks through the top, stalls on the denser layer and spreads sideways. A French drain set into that perched layer gives the water an easier path out.
Where will the water go?
Ask this before anything else. The outlet has to be lower than the trench. On the higher ground in west Mobile, Semmes and Tillmans Corner, finding fall is usually easier. In low parts of town near the bay or along tidal stretches of Dog River, there may be only inches of drop over a long run, and the trench depth has to follow the outlet, not the other way around. Common outlets are a pop-up emitter in a lower part of the yard, a roadside ditch or the street where allowed.
What should the quote spell out?
- Trench route, length and depth, and the fall from start to outlet
- Pipe type and size, stone and filter fabric
- Where the water discharges and how the outlet is kept from clogging
- Who submits the Alabama 811 request and how sod and beds get restored
The contractor sets the price after walking the lot, checking how much fall there is to an outlet and seeing what's buried in the way. We don't quote prices, and a number given over the phone before anyone has seen the yard is a guess at best.
Where we connect you with help
Common questions
How deep does a French drain need to be?
Deep enough to intercept the wet layer, but never deeper than the outlet allows. Water can't drain below the level where the pipe empties.
Will a French drain clog?
Fine silt can work into the stone over time. Filter fabric, clean stone and a cleanout port make it easier to keep the line flowing.
Related services
- Downspout drain lines
- Yard grading and swales
- Catch basins and channel drains
- Crawl space drains and sump pumps
More background: Mobile County drainage guide.
Back yard still a pond after the last Gulf storm?
Call the number above and get connected with an independent drainage contractor who works in Mobile County.