By the Earthstone Materials Team · Published September 22, 2026 · Last updated: October 4, 2026
South Florida rain does not negotiate. A French drain built with the right stone moves water away from the house for decades. Built with the wrong fill, it clogs and becomes an expensive trench.
How a French drain works
A sloped trench lined with landscape fabric holds a perforated pipe surrounded by clean stone. Water flows through the gaps in the stone, enters the pipe through its slots, and runs downhill away from the structure. The stone does two jobs: carrying water and keeping soil from reaching the pipe.
Which stone sizes work
- #57 stone (3/4 inch): the standard choice for French drains and drain fields. Angular, uniform, and open enough to move serious water.
- Larger riprap: for heavy-flow outfalls, swales, and spots where erosion is the enemy. Too big for a standard drain trench.
- Pea gravel (3/8 inch rounded): works in shallow landscape drains and dry creek beds, but the smaller rounded pieces leave less room for water and can shift over time.
Why angular beats rounded
Angular pieces lock against each other and hold their voids open even under the weight of soil above. Rounded stone never truly locks, so it migrates and settles, and the drain loses capacity. For anything buried and structural, angular wins.
Planning the trench
Give the pipe stone on all sides, not just underneath. A common approach is several inches of stone below the pipe with full coverage above it before the fabric wraps shut and soil goes back. Keep soil out of the stone with fabric, because soil in the voids is what kills drains. Unsure about sizing for your yard? Our drainage aggregates service covers the county, and a fast quote gets the right stone on the truck. You can also browse the full inventory.