This whole chemical interplay of detergent, dirt and water needs just the right mix of water and quantity and nature of surfactant molecule to take place appreciably. If there are too few surfactant molecules, and too little energy in the water, the surfactants will not be able to surround and carry away oil and dirt globules as described. However, too many surfactant molecules will cause a problem as well because they will stick to every fiber present and copious rinsing will be required to really rid the laundry of the thus resultant surfactant layer.
Surfactant activity is also affected by water hardness (mineral content of the wash water). Higher mineral ion content of wash water impacts the activities and availability of the surfactant molecules. The more minerals there are in the wash water, the less cleaning the surfactant molecules can actually do because mineral ions in the water react with the water loving head of the surfactant causing the molecule to fall out of solution thus rendering it completely unavailable as a surfactant.
There are different ways to address the problems that arise in a washing environment due to water hardness. More substances must be brought into the detergent mix in order to deal with wash water mineral content. The detergent Industry has turned to the use of powerful, and environmentally complex molecules to eliminate the impact of water hardness upon surfactant cleaning abilities. these molecules are call hardness sequesterants or water softeners. The new synthetic water softeners should be regarded with caution. Synthetic compounds time and again turn out to carry serious environmental impacts.
At any rate, there are other, more simple ways of addressing these laundry cleaning issues. Green laundry detergents will make use of these simpler solutions in their formulations. Washing Soda is the traditional hardness sequesterant. Green laundry detergents usually include washing soda in the mixture. This sequesterant does not have extremely serious or long term health and environmental impacts.