To remove water, mold, or mildew stains from concrete patios and driveways, use a hose or pressure washer. If stains persist, mix a solution of one-quarter bleach to one gallon of hot water and scrub the area with a brush, watering down nearby foliage first to prevent damage from runoff. Rinse thoroughly with clean water.

Sweep off or vacuum up any loose dirt, dust, and debris from the concrete surface. Using a garden hose, wet the concrete. Then, apply a mixture of trisodium phosphate and water, scrubbing the solution onto the surface using a stiff-bristled broom. You can also use a pressure washer for this step.

Pour warm water in a bucket and squeeze a small amount of dish soap in until suds form. Dip a bristle brush or another stiff brush in the soapy water and scrub it in circular motions to begin lifting the stain from the concrete. Rinse the area with fresh water from a garden hose.

Mix about 1/3 cup of bleach into a gallon of clean water in a plastic bucket or container Apply the bleach solution using a nylon-bristled brush or broom Scrub thoroughly Leave the bleach solution on the concrete for about 10 minutes

Combine the water and laundry detergent in a bucket and stir well. Dunk a hard bristle scrub brush into the soapy solution and use it to scour the dirty areas on the basement concrete using circular motions. Rinse and dunk the brush while cleaning the area to prevent spreading the dirt.