Mix a washing solution in a clean container. Mix 4 cups of white vinegar for every 1 gallon of water.
Pour the solution into the tank on your pressure washer.
Spray the solution onto the surface that is stained with calcium deposits. Most pressure washers come with multiple tips for various spraying purposes. Use a nozzle that allows a concentrated spray at a high pressure.
Wait 10 minutes as the vinegar breaks down the calcium deposits.
Brush down the surface with a nylon bristled brush. If some of the calcium deposits are still remaining after brushing, spray the area again with the pressure washer and repeat the brushing activity.
Rinse the surface once more with the water and vinegar solution. Follow with a plain water rinse with the pressure washer. For these final rinses, use a nozzle on the washer that creates a wider spray pattern.