Even if you're viewing with the naked eye that the raw water clean, but in fact it may contain contaminants that are not safe to bring the consumer should have to improve the quality of raw water first.
Even with the naked eye to see that the water is clean, but in fact it may be unsafe contaminants in consumer products should be introduced to improve the water quality before.
Even to see with the naked eye that the raw water, clean but as a matter of fact, it may contain contaminants, unsafe in the consumer to should have improved water quality first.