#TW4201609 Temporary Washouts

How many times have you seen stucco, mortar, and plaster trades make a temporary washout that you know is not acceptable? It happens all the time on construction sites, and due to the excessively high pH levels associated with of these cementitious products, it is crucial that the remnants of these products stay within the temporary washouts.

Why is it important?

  1. In the Construction General Permit under Waste Management it states, “Ensure the containment of concrete washouts that may contain additional pollutants so there are no discharges into the underlying soil and onto the surrounding areas.” (Attachment C, D, E)
  2. Your site could be issued a citation for faulty washouts
  3. It is detrimental to the environment as it kills fish and fauna in surrounding water bodies and pollutes groundwater

Ways to properly construct both ABOVE and BELOW grade temporary washouts:

  1. Temporary washouts need to be constructed a minimum of 50 ft away from storm drain inlets, open drainage facilities, and watercourses
  2. A designated sign should be installed adjacent to each washout
  1. All washouts need to be removed from the site BEFORE the container reaches 75% capacity
  2. Materials used to construct the temporary concrete washout should be removed from the site and properly disposed or recycled
  3. Only use plastic lining material of 10 mil inch polyethylene sheeting without holes, tears, or other defects that compromise the impermeability of the material
  4. Once the concrete waste is washed into the temporary washout and allowed to harden, the concrete should be broken up and removed on a regular basis
  5. Ensure the base of the washout is free of rocks or debris that may damage the plastic liner
  6. Portable removable containers can be used, also called “roll off”; this concrete washout facility should be properly sealed to prevent leakage

Above Grade:

  1. Recommended minimum length and width of 10 ft
  2. Use straw bales, sand bags, or wood frames to securely fasten the entire perimeter with two stakes to construct the temporary washout
  3. Minimum freeboard of 4 in

Below Grade:

  1. Recommended minimum length and width of 10 ft
  2. Dig a 3 ft hole and use lath, flagging, and sandbags to construct the perimeter of the washout
  3. Minimum freeboard of 12 in