Check your geographic and average rainfall.. but in this situation you may be able to benefit from a rain water washing program. I would also advise an RO WATER system as well. You can hook up a system and have it fill a 3-400 gallon tank on site and feed off that to fill your truck as well as use for washing.
Problems with well water: Higher iron and mineral depostis besides other naturally occuring minerals specific to your area.. This can clog up screens and filters on equipment, clog up heat exchangers in a hurry, force you to use more chemicals because half of the chemical is trying to attack the "soil" in the water instead of in the carpet/rug. And you'll have to worry about rust tinting if you have heavy iron levels.