What Are Drainage Rock Sizes and How Much Does It Cost?
Drainage rock sizes range from 3/4 inch to 2 inches, and costs typically run $30 to $60 per ton. Choosing the right size and estimating accurately saves money and prevents drainage failures.
The short answer
Drainage rock comes in sizes like 3/4 inch, 1 inch, and 1-1/2 inches, with 3/4 inch being the most common for residential drainage. As of June 2024, expect to pay $30 to $60 per ton for crushed stone, plus delivery. Pea gravel and river rock cost slightly more, $35 to $70 per ton. The exact price depends on your location and the amount you need.
Key takeaways
- 3/4 inch crushed stone is the go-to drainage rock for most projects.
- Costs range from $30 to $60 per ton, not including delivery.
- Always order 10–15% extra to account for compaction and waste.
- Larger rocks like 1-1/2 inches work better for heavy runoff or erosion control.
Whether you’re building a French drain, backfilling a retaining wall, or managing soggy spots in your yard, the right drainage rock makes all the difference. Size affects how well water flows through, and cost can swing by region and stone type. You need a clear picture of both to plan your budget and avoid expensive mistakes.
What sizes does drainage rock come in, and which is right for my project?
Drainage rock sizes range from 3/4 inch up to 2–4 inches, each suited to different jobs. For most home projects, clean angular stone is the top pick. Here’s how the common sizes stack up: Before you order, plug your dimensions into our crushed stone calculator to get a precise estimate.
- 3/4 inch: The most popular choice for French drains and downspout drainage. It’s easy to shovel and provides good void space.
- 1 inch: Slightly larger, often used for septic leach fields or heavy-duty drainage behind walls.
- 1-1/2 inch: Ideal for erosion control and large-volume runoff. It’s heavier and harder to move.
- 2–4 inch (riprap): Best for channel lining and slope stabilization, not typical for buried drains.
How do I calculate how much drainage rock I need?
Getting the right amount of rock prevents mid-project delays and wasted money. Follow a simple formula based on your trench or area dimensions.
- Measure the area: For a trench, multiply length (ft) × width (ft) × depth (ft). For a surface layer, use square footage × depth in feet.
- Convert to cubic yards: Divide cubic feet by 27. Most suppliers sell by the ton, so convert: 1 cubic yard of stone weighs about 1.4–1.7 tons.
- Add waste: Order 10–15% extra to account for compaction, spillage, and uneven trench bottoms.
- Use our gravel calculator to do the math instantly.
What does drainage rock cost per ton or cubic yard?
Prices depend on stone type, size, and your location. As of June 2024, here are typical ranges per ton:
- Crushed stone (3/4"–1"): $30–$50 per ton. This is the most affordable and widely available drainage rock.
- Pea gravel (3/8"): $35–$70 per ton. Smoother and round, but less stable for drainage.
- River rock (1"–3"): $40–$80 per ton. Decorative, but costlier for drainage.
- Delivery fees add $50–$150 depending on distance. Bulk orders often reduce the per-ton price.
- Use our gravel calculator to estimate total tons and avoid surprise costs.
What common mistakes or waste factors should I plan for?
Even a perfect calculation can go wrong if you forget real-world factors. Here’s what often trips up DIYers:
- Forgetting compaction: Stone settles over time, especially under foot or vehicle traffic. Add 10–15% more to maintain grade.
- Ignoring trench irregularities: Trenches are never perfectly flat. Deeper pockets mean more stone, so round up your depth measurement.
- Not accounting for pipe volume: If you’re placing a pipe in the trench, subtract its volume, but still add extra for backfill around it.
- Ordering too little: Running out mid-project leads to extra delivery fees and mismatched stone. Use a gravel calculator and always round up.
What are the different types of drainage rock and how do they compare?
Not all drainage rock is the same. The best choice depends on your project’s needs and budget.
- Crushed angular stone (granite, limestone): Locks together well, excellent for drainage. Most cost-effective.
- Pea gravel: Smooth and round, cheaper per bag but shifts easily and may require a retaining grid.
- River rock: Attractive and durable, but rounded shape means larger gaps and potential shifting. Better for surface decoration.
- Recycled concrete: An eco-friendly alternative, usually cheaper, but may have fines that slow drainage.
- Compare types with our crushed stone calculator and pea gravel calculator to see which yields match your area.
Should I install drainage rock myself or hire a pro?
Laying drainage rock is physically demanding but straightforward. Here’s when to DIY and when to call an expert:
- DIY is fine for: Small French drains, downspout drainage, or replacing gravel in a dry well. Basic tools and a strong back are all you need.
- Call a pro for: Large retaining walls, septic system leach fields, or any project requiring heavy excavation. Mistakes here can lead to costly failures.
- Labor cost: Professionals charge $50–$100 per hour, so a straightforward drain can cost $500–$1,500 installed.
- Always check local building codes for drainage projects. Permits may be required for large installations.
- For small projects, our gravel calculator helps you order the exact amount and avoid markups.
Questions this page answers
What size drainage rock is best for a French drain?
3/4 inch angular crushed stone is the standard for French drains. It provides enough void space for water to flow while being small enough to shovel easily. Avoid pea gravel as it shifts and can clog the perforated pipe. Always use clean stone, meaning no fines or dust.
How much drainage rock do I need for a 50-foot trench?
For a typical 50-foot trench, 1 foot wide and 1 foot deep, you need about 2.3 cubic yards, or roughly 3.5 tons. Use a gravel calculator to adjust for your exact depth and width, and add 10% extra for waste.
Does drainage rock cost more than regular gravel?
Sometimes. Drainage rock is usually clean crushed stone without fines, which is a specific product. Standard gravel with fines is often cheaper, $20–$40 per ton, but it doesn’t drain well. Expect to pay $30–$60 per ton for true drainage rock, as of June 2024.
Can I use pea gravel instead of drainage rock?
Pea gravel can work in some drainage applications, but it’s not ideal. Its round shape prevents it from locking together, so it shifts and can collapse around a pipe. For flat areas or decorative dry creek beds, it’s fine. For buried drains, stick with angular crushed stone.
How deep should my drainage rock layer be?
For a French drain, you need at least 12 inches of rock surrounding the pipe, with 2–3 inches below and 6 inches on top. For surface spread, 2–3 inches is typical. Always aim for enough depth to keep the pipe below the frost line in cold climates.
What’s the difference between washed rock and regular gravel?
Washed rock has been cleaned of dust and fines, so water flows easily. It’s essential for drainage. Regular gravel contains fines that compact and block water movement. You can spot washed rock by its consistent color and lack of small particles.
Do I need landscaping fabric under drainage rock?
Yes, landscape fabric or filter cloth is crucial. It wraps the trench, keeping soil from mixing with the rock and clogging the drainage layer. Skipping fabric is a common mistake that leads to failed drains.
Choosing the right drainage rock size and budget comes down to knowing your project’s needs. As of June 2024, expect to spend $30–$60 per ton for standard 3/4 inch crushed stone, the all-around workhorse for drainage. Use our gravel calculator to nail your quantity, and remember: always add 10–15% extra. With the correct size and a solid estimate, your drainage project will keep water moving for years.