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Alternate Sources


Below are examples of alternate sources of water that can be used in buildings and operation-based permises. Before proceeding to explore these options, do find out more on the requirements for each of them.

Rainwater Harvesting

The construction of rainwater collection systems for any purpose is regulated by Section 31 of the Sewerage and Drainage Act. Developers can build rainwater collection systems to collect rainwater for non-potable use within their own premises will have to satisfy a set of PUB conditions.

Download Guidance notes for the Application of Rainwater Collection Systems [PDF]. 

Greywater Recycling

The sources of Greywater are water discharged from showers, bathtubs, wash basins and laundry. As this is untreated used water not in contact with toilet waste, it excludes water from urinals, toilet bowls (water closets), kitchen sinks and dishwashers. 

Before Greywater can be reused for non-potable purposes like toilet flushing, general washing and  irrigation as well as make-up water in cooling tower, it has to go through membrane filtration for disinfection. Certain safety requirements for Treated Greywater must still be met. 

For public health reasons, it is however prohibited to use Treated Greywater for high-pressure jet washing, irrigation sprinklers and general washing at markets and food establishments. 

Download Guidance Notes for Treated Greywater Quality [PDF]. 

Download Technical Guide for Greywater Recycling System [PDF].


Industries located on offshore islands or along the sea front can consider using seawater for process and cooling.


Produced from treated used water that is further purified using advanced membrane technologies and ultra-violet disinfection, NEWater is ultra-clean and safe to drink. NEWater is mainly supplied to the businesses which need high-grade ultra clean water. They are also used as process water in industrial premises, air-conditioning cooling towers, irrigation/landscaping, etc.

Click here for more information on NEWater.

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