One of the common problems we deal with in detailing is hard water spots. Much of the problem in many areas may be attributed to the high level of calcium in local water supplies. This may be more prevalent when water from wells is used to wash cars at home or those who park near a sprinkler system that operates from a well are prone to unsightly spots on the finishes of their cars. 

The spots are caused by mineral deposits in the water. If the water is left on the car long enough, the deposits can etch the surface of the car. One method to solve the problem is by using an 800-, 1,200- or 2,000 grit compound -- depending on the severity of the water spots, how long they have been left on the finish, and the color and make of the car. 

After thorough high-speed buffing, a coat of wax is applied to shine the finish. Next a coat of one-year sealant/protectant should be applied. This should ensure a spot free finish for one year. The final step is to follow proper car washing procedures to avoid future problems.