wrote on Aug 13^th, 2012 at 9:17pm:

John, Thank you for the very usefull information. My concern is of water supplied from unknown sources,which at best will be agricultural water,or worse still from the river.( What would you recommend to test for,such as radioactivity,before commencing treatment ?

Phil,
there is no point in testing for radioactivity. There is no way to reduce it even if it's present. the chances of it being present in harmful amounts are almost nil - even from the  power station outflow on the river!

I would be more concerned with making sure the water is as clean and free from bacteria, viruses, fungi, Giardia, and  Cryptosporidium.

Let's put it this way, If I was having a well or cisterna built for drinking water (or even cleaning river water), I would be thinking along the lines of having the water pass through a slow sand filter with activated carbon layer to remove biological (algae for example) and chemical contaminants.

I would then have  a chlorination or ozone phase to kill micro-organisms, followed by  'point of use' filters to remove the killed micro-organisms.

There is plenty of good advice on the net and plenty of suitable under cupboard filters available for 'point of use' installation.

Hope this helps.
John