WATER-CLOSET CISTERNS (Replacement with direct-flow flush system)

[Mr Speaker in the Chair]

Mr Ng Yeow Chong asked the Prime Minister if he will ask the Public Utilities Board to consider the feasibility of replacing the present water-closet cisterns with a direct-flow flush system to economise water.

The Minister for Education (Mr Lim Kim San) (for the Prime Minister): Mr Speaker, Sir, I presume the "direct flow flush system" referred to by the Member is the spring-loaded flush valve system. If so, the Public Utilities Board would not recommend replacing the present water-closet cisterns with spring-loaded flush valves because they are much more expensive, costing about three times as much as the ordinary water-closet cisterns. Besides, they go out of order more easily, resulting in water being wasted as leakage from the valve flows directly into the water closet pan. Such leakage is also difficult to detect. Furthermore, the volume of flush is usually greater and cannot be controlled. Another objectionable feature of the flush valve system is that, in the event of its malfunction, it is possible for contamination of water due to reverse flow, to take place.

The Board has, however, in some instances, allowed the installation of flush valve systems in institutional buildings. Very stringent conditions to minimise waste and to prevent the possibility of contamination by the provision of a separate storage tank are laid down as conditions of such approval.