The three keys to clean pool water are circulation, filtration and sanitization. If any one of these is missing, water will not be clean. Filters should be cleaned regularly and replaced when the...
The cheapest (but more complex) way is to use reverse osmosis, which produces two water streams... one with less salt, and one very concentrated in salt (perhaps toxically so) and "floaties" that...
fitration,evaporation adding of purifing chemical like chlorine,sedimentation make water safe for drinking but a pure water(totally free from impurity) is got by distillation.