Is concrete washout allowed on a construction site?

Under EPA's 2022 CGP, yes, if the wash water goes into a leak-proof container or leak-proof lined pit and liquid waste is not discharged or disposed of on the ground (Parts 1.3.1 and 2.3.4). Texas authorizes land disposal of concrete truck washout behind structural controls or on minimal slopes (Part VI).

Where should a concrete washout area be located?

EPA's permit says as far as possible from receiving waters, drainage features and storm drain inlets, in a designated area used only for washout where feasible. Washington also bars washout in the footprint of a future infiltration BMP.

Does a concrete washout need to be on the SWPPP site map?

Yes under EPA's permit, which lists pollutant-generating activities such as washout on the site map, and under Texas (Part VI.E) and Mississippi (ACT5 T-13(10)).

What happens to hardened concrete in a washout?

EPA's permit says to remove and dispose of hardened concrete waste the same way as other construction waste (Parts 2.3.3e and 2.3.4).

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Concrete washout rules on construction sites

EPA's 2022 Construction General Permit prohibits discharging concrete washout wastewater unless it is managed: wash water goes into a leak-proof container or a leak-proof, lined pit sized so it cannot overflow, liquid waste may not go into drainage features, inlets or waters or be disposed of on the ground, hardened concrete is handled like other construction waste, and washout happens in designated areas as far as possible from waters and inlets. EPA 2022 CGP Part 1.3.1, 2.3.4 State permits differ: Texas allows land disposal of concrete truck washout behind structural controls or on minimal slopes, while still prohibiting any discharge. TXR150000 Part VI.A-C

National guide. The rules cited are from EPA's 2022 Construction General Permit (as modified in 2025), checked October 20, 2026, which applies where EPA is the permitting authority. Most states issue their own permit with different details; check your state before relying on a number.

Sources last checked October 19, 2026. Prepared by our team led by Mohamed Elansary, PhD, with AI research tools. We are not a licensed engineering firm and do not seal plans.

General information; your permit text controls. Not legal advice and not engineering judgment. We make no promise of permit coverage, agency acceptance or compliance.

EPA rules

Rule	EPA 2022 CGP
Concrete washout water	Prohibited discharge unless managed by an appropriate control as described in Part 2.3.4. EPA 2022 CGP Part 1.3.1
Stucco, paint, form release oils, curing compounds	Washout and cleanout wastewater is a prohibited discharge. EPA 2022 CGP Part 1.3.2
Container	Leak-proof container, or leak-proof and lined pit, designed so no overflow occurs from inadequate sizing or precipitation. EPA 2022 CGP Part 2.3.4
Liquid wastes	Not into drainage features, storm inlets or receiving waters; not infiltrated or disposed of on the ground; follow State, Tribal or local disposal rules. EPA 2022 CGP Part 2.3.4
Hardened concrete	Removed and disposed of the same way as other construction waste. EPA 2022 CGP Part 2.3.3e, 2.3.4
Location	As far as possible from receiving waters, drainage features and storm drain inlets; designated washout areas used only for that, to the extent feasible. EPA 2022 CGP Part 2.3.4
SWPPP	Washout is a pollutant-generating activity: list it with its pollutants and show its location on the site map. EPA 2022 CGP Part 7.2.3g, footnote 87; 7.2.4

How states differ

Permit	Concrete washout rule
Texas TXR150000	Land disposal of concrete truck washout is authorized at the site, in areas with structural controls (temporary berms, shallow pits, storage tanks with slow release) or on minimal slopes that allow infiltration and filtering. Discharge to surface water or storm sewers is prohibited at all times; washout during rain is minimized; it must not contaminate groundwater; washout areas go on the site map. TXR150000 Part VI.A-E
Florida CGP	Wastewater from concrete washout, and from stucco, paint and similar cleanout, is a prohibited non-stormwater discharge. FDEP CGP Part 3.3.1-3.3.2
Mississippi MSR10	Concrete wash water and other wash waters must be treated in a sediment basin or equivalent control before discharge. MSR10 ACT5 T-3(12) The scaled site map shows the concrete washout area. MSR10 ACT5 T-13(10)
Washington CSWGP	Concrete wastewater is a prohibited discharge. CSWGP S1.D.1 Truck washout happens off-site or in designated washout areas only, never onto the ground, into drains, ditches, streets or streams, and never in the footprint of a future infiltration BMP. CSWGP S9.D.9.h Sites placing more than 1,000 cubic yards of concrete over the project, where runoff reaches surface waters, sample pH weekly against an 8.5 benchmark. CSWGP S4.D

Note the difference: EPA's permit does not allow liquid washout waste to be disposed of on the ground, while Texas authorizes land disposal behind controls. Use the rule in the permit that covers your site; see the state hubs for which permit applies: Alaska, Arizona, Arkansas, Colorado, Florida, Hawaii, Idaho, Illinois, Indiana, Iowa, Kentucky, Louisiana, Massachusetts, Michigan, Mississippi, Nebraska, Nevada, New Hampshire, New York, North Dakota, Ohio, Oklahoma, Oregon, South Carolina, South Dakota, Texas, Utah, Washington, West Virginia.

Why it is regulated

Washington's permit lists concrete washing and curing waters, mixer washout and concrete pumping among pH-modifying sources that must be kept out of runoff. CSWGP S9.D.9.f Its pH benchmark is 8.5 standard units, and sites that reach it must keep high-pH water out of storm sewers and surface waters or neutralize it. CSWGP S4.D

What goes in the SWPPP

The washout activity, its pollutants, and the control used (container or lined pit, or the state's alternative). EPA 2022 CGP Part 7.2.3g, 7.2.6
The washout location on the site map, kept current within 7 days of a move. EPA 2022 CGP Part 7.2.4, 7.4.1
Inspection of the washout with the rest of the site's controls on the permit schedule. EPA 2022 CGP Part 4.2

What this page does not cover

Product or vendor selection, waste hauling, disposal permits and local rules. State and local disposal rules for liquid washout waste control.

Have it written for you

SWPPP Desk prepares site-specific SWPPPs from your drawings for construction sites in the states we cover (coverage by state), for a fixed price, delivered the next business day after your inputs are complete. Small site (1 to under 5 acres): $449. Large site (5 acres or more): $749. Background: all guides.

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