1 1/2 Inch Drain Rock (Size #4) Clean Wash Rock

Often called clean or wash rock, Size #4 Drain Rock runs from 1 1/2 inch down to 3/8 inch with no sand in the mix. Like all drain rock, the absence of fines is the whole point: the clean stone drains quickly and resists compaction, so it holds up in muddy ground and in any area affected by run-off or settling. The mid-range size makes it one of the most versatile drainage rocks for everyday use. It is a popular all-around choice for driveways, parking areas, and landscaping, especially in spots that stay soft or wet. Spread over mud-prone ground, it gives a stable, free-draining surface that stops the churning and rutting you get when water has nowhere to escape. The clean, uniform size also leaves a neat, finished appearance wherever it is used on the surface. Compared with the larger 2 1/2 inch drain rock, this grade is easier to spread and walk on and gives a tidier finish, while still moving plenty of water. That balance of drainage and a usable surface is why it suits both functional drainage layers and visible landscape areas. On wet Big Island sites where settling and run-off are common, it is a dependable fix. Common uses: Driveways and parking areas Mud-prone and low, soft spots Run-off and settling areas Drainage layers and trenches Landscaping and ground cover Good to know: Crushed rock from 1 1/2 inch down to 3/8 inch No sand, so it drains well and resists compaction Easier to spread and neater than 2 1/2 inch drain rock Doubles as a functional and a decorative su Sold on Hawaiian Volcanic Organic Farm (https://hawaiianvolcanicorganicfarm.com/products/1-5-inch-drain-rock). The price shown is the retail price on that storefront on 2026-10-24, not a GreenB2B quote or a wholesale price.