A. Washing your car at home is extremely harmful to the finish. Tests conducted by the University of Texas proved that a single home hand-wash can leave scratches in the finish as deep at 1/10 of the paint's total thickness. And, that the average garden hose can't supply enough water and water pressure along with the detergent action to avoid damaging a car's finish.
This important study concluded that automobile owners should avoid washing their cars at home. Only a professional carwash can provide the proper amounts of water and water pressure needed along with the appropriate, professional cleaning solutions to safely and effectively clean your car.