Hire A Professional
The best and only way to properly clean your driveway is to hire a professional. Not only will they get it done right the first time, they will also do it in such a way that nothing will be damaged. There is potential to damage concrete. Yes, concrete is susceptible to etching from high pressure nozzles on power washers. Also, your plants are susceptible to damage if you use too much of any of the necessary cleaning agents. First, a professional will remove any large debris from the driveway. This could include branches, leaves, or rocks. Then they will look to see where the majority of the mold and mildew is growing. They will apply a soap to the entire surface. This soap is made of three ingredients, bleach, surfactant, and water. The bleach kills the bacteria and mold. The surfactant is your basic laundry detergent that is used to lift the grease and grime from the cervices of the concrete. The water dilutes the active cleaning agents. They will let this sit as the use a scrub brush on the surface. Finally, they will gauge the integrity of the concrete and apply an appropriate amount of pressurized water from a power washer. It will most likely be more than your garden hose but less than a full pressure washing system. These systems can be 50 times more powerful than a garden hose and can etch you concrete.
Don’t Do It Yourself
You can do this yourself if you are willing to live with the results that range from etched and damaged surfaces to dead grass and plants. It may even take you multiple trips to a hardware store, multiple days to complete, and multiple washing sessions to get it right. Instead of this waste of time, hire a professional to get the job done right the first time.