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Code of Practice


Singapore is situated close to the equator and is subjected to heavy tropical rainstorms. The average annual rainfall in Singapore is about 2,400 mm. There are no distinct wet or dry seasons as rain falls every month of the year. The two main seasons, the North-east monsoon season (from late November to March) and the South-west monsoon season (from late May to September) refer to the prevailing winds dominant at the time of the year. The transitional months (or Inter-monsoon period) separating the two monsoons are April to early May, and October to early November.


The total land area of Singapore is approximately 712.4km2 (as at 2010). This area comprises the mainland and other islands. The mainland measures 49 km from east to west and 25 km from north to south with a coastline of 189 km. The topography of the main island of Singapore is undulating with its highest point, the Bukit Timah Peak at only 163 m above mean sea level. Much of Singapore lies within 15 m of mean sea level and the ground levels of some 30% of Singapore are less than 5 m above mean sea level.


This Code of Practice on Surface Water Drainage is issued under Section 32 of the Sewerage and Drainage Act (Chapter 294). It specifies the minimum engineering requirements for surface water drainage for new developments. The Qualified Persons shall ensure that all aspects of surface water drainage are effectively taken care of in their planning, design and implementation of the development proposals.

Public Utilities Board

Last updated on 29 Nov 2011