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How to Clean a Block Retaining Wall

April Dowling

Retaining wall systems aesthetically enhance landscapes, control erosion and eliminate steep slopes. Concrete cinder blocks are an ideal building material for retaining walls, due to their strength and longevity. Although cinder block retaining walls are durable, they are not impervious to dirt accumulation.

Remove dirt and grime from cinder block retaining walls to improve the appearance.

Exposure to soil, water drainage and air-borne dust particles causes retaining walls to appear dingy. Regularly cleaning cinder block retaining walls maintains their appearance and improves a landscape’s overall appeal. Basic cleaning solutions can effectively clean cinder block retaining walls.

  1. Attach a spray nozzle to the end of a garden hose. Spray the cinder blocks with water from the garden hose to rinse off loose dirt, dust and other debris. Wash from the top of the wall downward.

  2. Inspect the wall for remaining stains and stubborn grime buildup. If more cleaning is needed, fill a 3-gallon plastic bucket with 2 gallons of warm water. Add 2 tbsp. of mild liquid dish soap to the water. Thoroughly mix the solution.

  3. Lay plastic tarps at the base of the wall. Thoroughly cover the ground with the tarps to protect vegetation from runoff.

  4. Scrub the cinder blocks with the soapy water, using a nylon scrub brush. Clean from the top of the wall down. Immediately rinse the soapy cinder blocks with water from the garden hose.

  5. Rinse the entire retaining wall with water from the garden hose to remove any remaining grime and soap.

  6. Allow the wall to air-dry. Repeat the cleaning process if necessary.

  7. Tip

    Remove extremely stubborn stains with a solution of hydrochloric acid and water. Follow the acid manufacturer’s instructions on the product’s label.


    Do not use pressure washers on cinder block retaining walls; excessive water pressure can cause dirt and stains to become embedded in concrete.