Drinking Water

Mr. Gareth Wardell
To ask the Secretary of State for Scotland what is the percentage by volume of drinking water in Scotland that is treated by the addition of (a) chlorine and (b) ozone.

Lord James Douglas-Hamilton
Over 99 per cent. of drinking water in Scotland is disinfected by chlorination. Of the remainder, broadly equal proportions are disinfected by either ozone or ultraviolet radiation.