I don`t even bother washing my car in this little sh*thole town because we have town water and it spots my car almost instantly. My mother lives about 20-25 min away, but she has well water and it doesn`t leave embedded water spots on my glass etc. I don`t want to get a deionizer pressure washer because (from what I understand) the filters don`t last very long and they aren`t cheap. If I could figure out the most common minerals that cause the problems though I could buy the appropriate filters for each mineral, etc. I had a water test done by my plumber a while ago, but I don`t know what the results were. I just wanted to make sure it was safe for the dogs to drink. I hadn`t been here long enough to realize how junk the water was here for cars.