HC Deb 18 January 1990 vol 165 c369W
Mr. Gareth Wardell

To ask the Secretary of State for Wales what is the percentage by volume of drinking water in Wales that is treated by adding(a) chlorine and (b) ozone.

Mr. Grist

I am informed by Dwr Cymru that the information is as follows:(a) over 99 per cent.; (b) none.