To reduce iron stains on laundry caused by hard water, use a laundry detergent specifically designed for hard water. Laundry detergent that contains baking soda, washing soda or oxygen bleach can also be used to reduce hard-water stains.
Laundry detergents that contain baking soda can be used to control stains caused by hard water. Regular laundry soap can be used in hard water, but the amount of soap used must be increased to clean the clothes properly. Follow the directions on the packaging to use the correct amount of soap. Some additives, such baking soda or washing soda, can be added to regular laundry detergent to reduce stains caused by hard water. To use washing or baking soda to eliminate iron and mineral stains, add a cup of the soda to each load of laundry along with regular detergent.