hello dear one's water is most important thing in our life. we need water in cooking, showering, etc but the most important use is for drinking. we know that our climate and our natural resources are getting polluted and water is one of them so getting back on topic when we need water purifiers??? it depends on what type of water supply you are using 1.muncipal 2.salty water 3.ground water 4.tanker 5.rain water answer is you need water purifiers in all of them but which one??? water purifiers are divided in categories 1.uv water purifiers 2.RO water purifiers 3.RO+UV water purifiers 1.let's talk about uv water purifiers it just a normal water purifiers which purify municipal or which governmental water which to provide you in simple words if your water quality is soft (not hard water) than you need to use uv machin. if your water tds range is 30-60 2.if provide water is hard water than you need to buy RO machine (if water tds is more ...