Pit Run Gravel: What It Is, Uses, Sizes and Driveway Tips

Pit run gravel is about as raw as aggregate gets. A loader digs it out of a gravel pit and drops it in a truck, with no crushing, washing or careful screening in between. What you get is nature's mix: sand, rounded pebbles, bigger stones and sometimes a few cobbles. Because it skips processing it is one of the cheaper materials a pit sells, and it shows up as fill, as a bottom layer on rural driveways and as a quick fix for soft ground. This guide explains what it is, where it makes sense and where you should pay for crushed stone instead.

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Quick facts

What it is: unprocessed natural gravel and sand straight from a pit.
Spec definition: Wisconsin DOT's standard specifications define pit run as unprocessed aggregate from a gravel pit with mostly 1 1/2-inch or larger particles.
Shape: mostly rounded, because the stones were worn by water and ice long before they were dug.
Consistency: it varies, sometimes a lot, from load to load.
Common uses: bulk fill, raising grade, the lowest layer of a long driveway, temporary access roads.

Pit run vs processed gravel

Material	Processing	Shape	Best job
Pit run	None, or a coarse screen to drop boulders	Rounded	Fill, subbase, building up grade
Bank run	None (name overlaps with pit run)	Rounded, often sandier	Fill, backfill
Crusher run	Crushed to a controlled size range	Angular	Compacted base under driveways and slabs
Washed stone	Crushed or screened, then washed	Angular or rounded	Drainage layers, decorative top

Why pit run is a bottom layer, not a top layer

Rounded stones do not interlock the way crushed faces do. Under tires they shift and roll, so a pit run surface ruts and throws stones. Large cobbles also work their way up over time and leave a lumpy driveway that is hard to grade. On the other hand, a thick layer of pit run is a cheap way to bridge soft ground, raise a low area or build bulk under a better material. That is why many rural driveways are built as pit run on the bottom, a few inches of crushed base in the middle, and a finer crushed stone on top. The steps are laid out in our gravel driveway build guide.

Watch the fines and the clay

Because nothing is washed out, pit run carries whatever the pit holds. Some loads are clean sand and gravel that drain well. Others carry silt or clay that holds water and turns soft in spring. Before you order a large amount, squeeze a damp handful: if it smears and holds a shape, it is carrying a lot of clay. Engineered projects test gradation and plasticity for this reason, and many state specifications only accept natural gravel as base after it is processed to a set gradation. On a home project, put a clean crushed layer on top so the surface drains, and think about a geotextile fabric where pit run sits on soft clay.

Using pit run to fix soft spots

When a driveway has a section that pumps mud every spring, the usual fix is to dig out the soft material and replace it with something that drains and carries load. Coarse pit run is often used to backfill these holes because it is cheap and bulky. Place it in layers, compact each layer, and cap it with crushed base. For very soft ground, contractors may use larger crushed rock instead; our undercutting soft spots guide covers the process.

How much pit run do you need?

Measure the length, width and depth, convert to cubic yards, then to tons with the weight your pit quotes. A made-up example:

Driveway subbase: 12 feet wide, 200 feet long, 8 inches deep.
Volume: 12 × 200 × (8 ÷ 12) = 1,600 cubic feet, or about 59 cubic yards.
If the pit quotes 1.4 tons per cubic yard (an assumed number for this example), that is about 83 tons, before any allowance for compaction or soft spots.

The gravel calculator does this with your own density, and how many tons of gravel fit in a dump truck helps you count loads. For the crushed layers above, use the base calculator or the crushed stone calculator.

Tips before you order

Ask for the top size. "Pit run" from one pit can be 3-inch minus, and from another can include softball-size cobbles.
Look at the pile. A visit tells you more about sand, clay and cobbles than any product name.
Ask if it is accepted for your job. If a town or engineer has a spec for the road base, check before buying.
Plan the cap. Budget for crushed stone on top so you are not driving on rolling rock.
Compact in layers. One thick dump-and-spread will settle unevenly.

Questions people ask

What is pit run gravel?

It is gravel as it comes out of the ground at a gravel pit: a natural blend of sand, rounded gravel and larger stones that has not been crushed, washed or screened. Wisconsin DOT's standard specifications describe pit run as unprocessed aggregate from a gravel pit with mostly 1 1/2-inch or larger particles.

Is pit run gravel good for a driveway?

It makes a decent bottom layer on a long rural driveway or a soft spot, because it is cheap and bulky. It is a poor top layer: the rounded stones roll, cobbles poke through, and the mix varies load to load. Cap it with a crushed base and a finer crushed surface.

What size is pit run gravel?

There is no single size. Pits often sell it by a top size such as 3-inch, 4-inch or 6-inch minus, and some loads include bigger cobbles. Ask what screen, if any, it has passed over and look at the pile before you order.

What is the difference between pit run and crusher run?

Pit run is natural and unprocessed, so its stones are mostly rounded and its gradation changes from one part of the pit to another. Crusher run is quarried rock run through a crusher, giving angular pieces with a controlled mix of sizes that compacts into a tight base.

Is pit run the same as bank run gravel?

The names overlap and are used loosely. Both refer to unprocessed natural gravel. In some areas bank run means a finer, sandier mix from the face of a bank, while pit run means coarser material with cobbles. Ask your supplier what their product contains.

How do you compact pit run gravel?

Spread it in layers, moisten it if it is dry, and compact each layer with a heavy roller or a large plate compactor before adding the next. Pull out oversized boulders that keep the roller from bearing down evenly.

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