We thank Mr Lee Swee Mun for his letter (Step up security of our waterways; June 20).

We recognise Mr Lee's concerns about the security implications on our water supply and would like to assure him that the safety of our water supply is of utmost priority.

This is why PUB has invested in a comprehensive and rigorous water quality monitoring programme that covers the entire water system from "source to tap" to ensure that our tap water is clean and wholesome.

In particular, reservoir water quality is monitored round the clock by online sensors and changes in raw water quality are picked up quickly for early intervention and assessment before the water is sent to the waterworks for treatment. Abstraction from a particular reservoir can be stopped should there be any anomaly in raw water quality.

PUB officers also conduct daily patrols of our reservoirs for general surveillance and supplement this with the use of technology. This includes the use of Unmanned Aerial Vehicles at Marina Reservoir, and CCTVs along our canals and reservoirs. We urge the community to also play their part in safeguarding our waters.

Ridzuan Ismail

Director, Catchment and Waterways

PUB