You have highlighted very good points about water importance that how much it is important to value One drop of water. I know that many people thinks that one drop don't have a value because a drop is very little but if we notice this thing that if we add a lot of drops then it becomes a pool of water so in this world there are different people who are living and if everyone is wasting just One drop of water then we cannot imagine that how much large quantity of water we are wasting everyday.

Even in our life what it has a lot of importance because we do a lot a activity with water and without water we cannot live even we will die if you don't drink water for a week. I am a muslim and I know that how much it is difficult to spend one day without water because we fast in Ramadan month that's why it is very important to have fasting in this month so that we may realise that how much the blessings that we have in our life and that we not consider too much are basically a lot for us and for our life.

We should always drink a water which have no containments because contaminants is a different thing even if you have access of different salts or metals in the water then you will also get a lot of diseases like goitre due to the deficiency of iodine and dental fluorosis due to the excess of flouride.

Success for you