Cold water Requires a cold water detergent to get clothes clean. If a cold water detergent is not available, dissolve detergent powder in hot water before adding it to the wash water. Requires more detergent than warm water to get clothes clean. Does not kill germs unless a disinfectant is added. Recommended for washing some delicate fabrics.
Water reaching the washing machine is cooler than in the water heater.
For very hot water in the washer, it may be necessary to set the water heater temperature on high. When using soap rather than detergent, soft water cleans clothes better than hard water. Hard water, which contains mineral deposits, requires more soap or detergent, and clothes don't get as clean as they do in soft water. Minerals in hard water combine with soap to form a scum, which causes laundry problems. Detergents work well in soft or hard water unless the water is especially hard.