Drinking water
Drinking water treatment techniques used in addition to public infrastructure - Household water treatment

Whether you're dealing with water that has deteriorated during distribution, or using "raw" water, the choice of treatment depends on the composition of the water and its use. First of all, you need to know your water through analysis, and define the purpose of the treatment. You don't need to demineralize water for watering, or disinfect water for central heating. It's a question of designing a system that takes into account both technical and economic aspects.