Concrete Washout Containment Volume

Sizes the lined pit or container that catches chute and pump rinse so high-pH slurry never reaches the ground or a storm drain (required by the CGP): required volume = trucks x washout / 7.48 x (1 + freeboard); pit side = sqrt(volume / depth). 20 trucks at 50 gal each is 1,000 gal - 154 cf (5.7 cy), a ~9 ft square pit at 2 ft deep. Built for the whole day's washouts, not one truck; the CGP governs containment.

total_gal = trucks x washout_gal_per_truck; required_cf = total_gal / 7.48052 x (1 + freeboard_pct/100); required_cy = required_cf / 27; pit_side_ft = sqrt(required_cf / pit_depth_ft).

Washout-containment identity by name (volume from trucks x per-truck washout, plus freeboard; pit side from volume / depth); first-principles volume arithmetic.

The containment volume is public quantity geometry; the SWPPP / CGP requires the containment and the disposal.

Estimate. AHJ and licensed professional govern.

Field names used by the API: trucks, washout_gal_per_truck, freeboard_pct, pit_depth_ft, total_gal, required_cf, required_cy, pit_side_ft

• Per-truck washout ~50 gal/truck default (chute and pump rinse plus returned slurry); the crew tunes it to practiceplanning estimate
• Containment lined pit or container per the SWPPP / CGP, cleaned out at ~three-quarters full; no discharge to ground or stormSWPPP / construction general permit