How do you dispose of concrete?

US C&D debris, 2018

600 million tonsEPA estimate

Directed to next use

455 million tonsEPA, aggregate was the main use

Sent to landfill

145 million tonsEPA estimate

Stormwater permit threshold

1 acre disturbedEPA NPDES

Short version

• Concrete recyclers take clean rubble and crush it into usable aggregate.
• C&D landfills and roll-off dumpster services accept it when recycling is not available.
• Broken concrete can often be reused on the same site as fill, subbase, or bedding.
• Call ahead — every facility sets its own limits on rebar, dirt, and contamination.
• Washout water is regulated separately, under state and local stormwater programs.

Where can you take broken concrete?

Broken concrete goes to one of three places: a concrete or C&D recycler, a construction and demolition landfill, or back into the ground on your own site. Which one applies depends on how much you have, how clean it is, and what operates near you.

Concrete recyclers and crushing operations are the first call. Many accept clean rubble at a lower tipping fee than a landfill charges, and some accept it free when the load is clean, because the material has value to them.

C&D landfills accept concrete along with other construction debris, usually by weight. Roll-off dumpster services will haul it, though concrete-only dumpsters are often smaller than general debris containers because of the weight.

Acceptance rules vary by facility, and there is no national standard. Call before you load. Ask specifically about embedded rebar and wire mesh, dirt and vegetation, asphalt mixed into the load, and any painted or coated surfaces. A contaminated load can be rejected at the gate after you have already paid to haul it.

Household quantities are different from jobsite quantities. Some municipal transfer stations accept small amounts from residents; most do not accept concrete in curbside trash at all.

How is concrete recycled?

Concrete is recycled by crushing it into aggregate. EPA notes that asphalt, concrete, and rubble are often recycled into aggregate or into new asphalt and concrete products, and that aggregate was the main next use for C&D materials overall.

The process is mechanical. Crushers reduce the rubble, magnets pull out reinforcing steel, and screens sort the output into size fractions. The result substitutes for virgin crushed stone in road base, backfill, and drainage applications, and in some cases as aggregate in new concrete.

The environmental case is the reason EPA promotes it. Recovering concrete avoids mining and processing virgin material, conserves landfill space, and keeps the material in productive use. EPA also points to the employment and economic activity that C&D recycling generates.

Cleanliness governs value. Rubble with soil, wood, gypsum, and trash mixed in costs more to process, and a facility may downgrade or refuse it. Separating concrete from the rest of the demolition debris at the source is what makes recycling work.

How much concrete waste does the US produce?

Construction and demolition materials are one of the largest waste streams in the country. EPA’s 2018 fact sheet estimates that 600 million tons of C&D debris were generated in the United States that year — more than twice the amount of generated municipal solid waste.

Of that total, just over 455 million tons were directed to next use and just under 145 million tons went to landfills. Aggregate was the main next use for the material in the stream.

The generation side is dominated by demolition, which EPA puts at more than 90% of total C&D debris, with construction accounting for less than 10%. Concrete is one of the bulky, heavy materials EPA lists as characteristic of the stream, alongside wood, asphalt, gypsum, metals, and brick.

Those numbers explain why so much infrastructure exists for handling concrete specifically. In most metropolitan areas a recycler is closer than a landfill.

Can you reuse broken concrete on your own site?

Reusing concrete on site is often the cheapest disposal route, and EPA lists it as standard practice: brick, concrete, and masonry can be recycled on site as fill, subbase material, or driveway bedding. Onsite reuse also avoids hauling costs entirely.

Broken slab pieces are commonly reused as fill behind retaining structures, as a base layer under new flatwork, and as rough bedding for gravel drives. Larger flat pieces get stacked as informal landscape walls and steps.

Two cautions apply. First, protruding rebar has to be cut flush — it is a puncture hazard and it will not compact. Second, concrete used as structural fill has to be broken down to a workable size and compacted in lifts; dumping chunks into a hole creates voids that settle later.

Local rules on placing fill vary widely and can involve grading permits, floodplain restrictions, or wetland setbacks. Confirm with your local building or planning department before burying anything, and never place fill where it changes drainage onto a neighbor’s property.

What are the rules for concrete washout?

Concrete washout — the water and residue from rinsing chutes, tools, and mixers — is regulated as a stormwater discharge, and the requirements come from state and local programs rather than a single federal number. EPA lists concrete truck washout among the pollutants commonly associated with construction sites.

The federal floor is the construction and development effluent guidelines, the “C&D rule” at 40 CFR 450.21, which prohibits the discharge of wastewater from concrete washout unless it is managed by appropriate controls. In practice that means a contained washout area — a lined pit or a prefabricated container — where the water evaporates or is hauled off and the hardened residue is removed as solid waste.

Permit coverage is triggered by disturbed area. A Clean Water Act permit is required for stormwater discharges from construction disturbing one acre or more, or less than an acre where the work is part of a common plan of development that will ultimately disturb an acre or more.

Sites under those permits must develop and follow a stormwater pollution prevention plan, or SWPPP, that meets the requirements of the applicable state or EPA construction general permit. EPA publishes a SWPPP template for its own permit.

Most states administer their own NPDES programs, so the specific best management practices you must follow are set locally. Check with your state environmental agency before assuming EPA’s permit applies to your site.

Common mistakes

• Putting concrete in a regular trash dumpster — weight limits and material restrictions usually make it a rejected load or a surcharge.
• Hauling a contaminated load to a recycler — dirt, wood, and trash mixed with rubble can get the whole load turned away at the gate.
• Rinsing the chute onto the ground or into a storm drain — washout discharge is prohibited under the federal C&D rule unless it is contained.
• Burying chunks as fill without compacting — voids between pieces settle, and whatever you build on top settles with them.
• Assuming one national rule covers washout — states and municipalities run their own programs with their own required practices.