The Inter-Agency Drainage Review Committee released its recommendations on the PUB website on Friday for public consultation.
Among them include suggestions that the ground level of buildings should be 60 cm above the road or highest-recorded flood levels, while humps before the basement entrance of buildings should be raised from 15 cm to 30 cm.
Other suggestions include defining more clearly the amount of rainfall drains can hold, based on catchment area or the importance of the development.
Associate Professor Vladan Babovic from the National University of Singapore's civil engineering department termed the recommendations "timely and prudent". He said, "There are a lot more paved areas than, say, 15 years ago, so rainwater flows much faster into our drains."
President of the Singapore Institute of Architects Ashvinkumar Kantilal told Today newspaper, the costs to adopt the changes would be "negligible" for new buildings but existing ones could find it "technically challenging" as they may not have "sufficient dimensions" to meet the requirements.
He suggested, the authorities could provide a grant or subsidy to help defray the cost of implementing the changes in existing buildings.
While Singapore's flood management strategies remain relevant, "a review of the drainage design standards was carried out in view of the uncertainties in weather patterns and an increasing number of flash flood incidents, such as the ones in June and July 2010," said PUB.
In tandem with the Intra-Agency Drainage Review Committee, PUB also convened an External Panel to review the drainage review proposals.
The panel suggested incorporating alternative design approaches, such as detention ponds to help mitigate constraints like limited land for widening.
"The proposed changes to land reclamation level are adequate but it would be advisable to carry out a sensitivity analysis and also to align them as part of an overall climate change adaptation strategy," the panel added.