Drain Rock for Florida French Drains, Walls and Leach Fields

Tip a yard of drain rock out and what stands out is how little sticks to anything. No gray film on the shovel, no dust rising, nothing caking on a wet day. That scrubbed look is the specification rather than a nicety, and on a lot where the water table sits a few feet down and a July storm puts water against a wall in ten minutes, it is the difference between a detail that drains and a strip of buried gravel that does not.

The washed 3/4 to 1-1/2 inch spec, read one line at a time

Three things are stated about this material and each one changes how you use it.

Size runs 3/4 inch to 1-1/2 inch. That is a wider band than a single-number grading, and it is deliberate: a spread of sizes in this range still leaves large connected voids while filling a trench without the bridging you get from very uniform stone.

Washed to remove fines and dust. Fines are what kill a drain. A stone that arrives with powder on it carries that powder into the voids the first time water moves through, and the run silts from the inside. Washing takes that out before it is loaded.

Rounded or angular varieties. This is the line most buyers skip. Rounded pieces bed easily and look better where the stone stays visible. Angular pieces hold their void structure better under load, because they prop each other apart instead of rolling into a tighter arrangement. Ask for angular where anything sits on top of the drainage zone, and take either where it does not.

Where drain rock belongs on a Florida lot, and where it does not

Leach fields, wall chimneys and a water table that rises in June

Everything on that list depends on the same thing: somewhere lower for the water to go. Between roughly late May and October the water table comes up, and a trench cut below it stands full whether or not it is working. That is not a fault in the stone. It means the outfall has to be established first and the trench depth worked back from it, because water cannot fall to a point that is under water.

The second Florida factor is sand. Fine quartz grains travel in moving water and will find the voids you just paid for, so non-woven filter fabric lining the trench and lapped over the top of the stone is not an optional refinement here. On leach field work, follow the approved detail rather than a general rule; the stone is one component of a permitted system.

Behind a wall, keep the drainage zone continuous from the base of the wall up, and make sure the outlet at the bottom actually daylights. A chimney of clean stone that ends in a blind sump does nothing except store water where you least want it.

A rock garden bed and a shed floor: one is a maybe, one is a no

Both come up, and they deserve different answers.

A rock garden or xeriscape bed will work with this material. It does not decompose, it does not blow around, and the washed surface stays clean. What it is not is a decorative product: color and shape are whatever the batch gives, and the mix of rounded and angular reads less deliberately than stone chosen for looks. River Rock is the better call where the bed is a feature rather than a filler.

A shed or garage pad is a firm no. Open washed stone will not compact into a bearing layer, and a pad built on it will move. That layer wants Limerock Base built to depth and rolled, with anything else placed over it.

Yardage for a 30-foot downspout run and a 9 by 12 rock bed

The river rock calculator takes length and width in feet and depth in inches, handles rectangles, circles and up to five separate areas, and adds five percent by default. It works (L x W x D/12) / 27 = cubic yards, then applies density for tons. There is no published weight for this exact material, so use the site's closest listed family, crushed stone at #57 and 3/4 inch size, at about 2,800 lb per cubic yard or 1.40 tons per yard, and treat the tonnage as approximate since this grading runs coarser and may include rounded pieces. Three hypothetical jobs:

• A downspout run and soak trench, 30 ft long by 2 ft wide, 8 inches deep. 30 x 2 x 0.667 = 40 cubic feet. 40 / 27 = 1.48 cubic yards. 1.48 x 1.40 = roughly 2.1 tons.
• A rock garden bed, 9 ft by 12 ft at 3 inches. 9 x 12 = 108 sq ft. 108 x 0.25 = 27 cubic feet, which is exactly 1 cubic yard, or roughly 1.4 tons.
• A drainage chimney behind a 24 ft wall, 12 inches wide and 3 ft high. 24 x 1 x 3 = 72 cubic feet. 72 / 27 = 2.67 cubic yards. 2.67 x 1.40 = roughly 3.7 tons.

Put your own dimensions into the river rock calculator, which is the tool this material is set up on, and take the result as a guide rather than a guarantee at this grading.

Getting a washed load tipped where you actually need it

Order the quantity and the date on this page. Delivery is arranged at checkout by ZIP code, and the driver needs a clear approach and room to raise a body.

Have the trench open and the outfall settled before the load arrives, because washed stone left in a heap through an afternoon storm picks up whatever it is sitting on. Choose the tip spot on firm ground well back from the trench edge so nothing is driving along the lip of a fresh cut, and on a low lot pick the highest spot you reasonably can. Two people with shovels and a wheelbarrow will place a couple of yards into a trench without much trouble; beyond that a machine earns its place.