French Drain vs Regrading vs Dry Well: Which One Your Yard Needs

Every drainage company has a favorite tool. Ours is the one that matches where your water stands and where it can legally go. Here is how the three main fixes compare on a Jacksonville lot, and how we choose.

French drain: collect and carry

What it is. A trench lined with filter fabric, a perforated pipe on a bed of washed gravel, gravel to within a few inches of the surface, then sod or river rock on top. Water enters the gravel along the whole length, drops into the pipe and flows to an outlet.

Best for. A wet strip that follows a line — along a fence, between two houses, across the back of the lot where the hardpan pushes water sideways. Also the standard way to intercept a neighbor's runoff before it reaches your house.

Not for. A lot with no outlet. A French drain has to end somewhere lower than it starts; on a flat lot with the water table 2 feet down, that outlet is a dry well or a street connection, and the drain is only as good as that outlet.

Cost. $20 to $45 per foot installed in our area; a typical 50 to 100 foot run is $2,000 to $6,000.

Regrading and swales: make gravity do it

What it is. Re-shaping the soil so the surface slopes away from the house and toward a shallow, wide, grassed channel (a swale) that carries water to the street or a retention pond. No pipe, nothing to clog.

Best for. Lots that were graded flat or settled flat — common in subdivisions in Fruit Cove, Oakleaf and Nocatee a few years after the sod went down — and the strip between houses where the original swale has filled in. Also the first thing to check on a house where water sits against the foundation on one side.

Not for. Water that comes up from below, or a lot that is already the lowest thing on the street. You cannot grade your way out of a high water table.

Cost. $1,000 to $5,000 depending on the area moved and the sod replaced.

Dry well: send it down

What it is. A buried chamber — a plastic unit or a gravel-filled pit wrapped in fabric — that holds a storm's worth of water and lets it seep out slowly below the hardpan or into a sandier layer.

Best for. Lots with no legal outlet: no curb, no swale, a neighbor on every side. Also as the end point for downspout lines when the street is too far.

Not for. Coastal and riverside lots where the water table is within 2 feet of the surface in summer — a dry well in saturated ground is a bucket in a bathtub. We test the hole before we build one.

Cost. $1,000 to $3,000 per well.

How we decide

1. Downspouts first. If the roof is dumping at the wall, nothing else is judged until that is fixed.
2. Where does the water stand, and where is the lowest legal exit? A level and a walk after rain answer most of it.
3. Surface or subsurface? Water that arrives from the surface is a grading problem. Water that stays after the surface dries is a hardpan or water-table problem — pipe and gravel.
4. Combine when it is honest. Many yards get a short French drain feeding a regraded swale, with downspouts tied in. Few need all three plus a dry well — and we say so.

The inspection is free and the plan comes with a written price. (904) 561-1816.