A common issue for car owners is water spots. These are caused by minerals found in the water supply and are allowed by the EPA to be up to 500 parts per million. Ways to combat this are to use in-line filters or de-ionizing systems that use minerals to reduce these amounts.An easy way is to head on over to ZeroWater.com Then input your zip code on the bottom right.Here is an example of my reading! The higher the reading the higher the mineral content which leads to easier water etching, spotting, and will inform you if your water is nothing to worry about or whether you are asking for issues by letting it remain on your paint.Thanks for reading!