Water Pollution Control and Drainage Act
(Chapter 348, Section 71)
Sanitary Plumbing and Drainage Systems Regulations
Rg 2
(25th March 1992)
[15th June 1976]
1.  These Regulations may be cited as the Sanitary Plumbing and Drainage Systems Regulations.
2.  In these Regulations, unless the context otherwise requires —
“Code of Practice” means the Code of Practice on Sanitary Plumbing and Drainage System issued under regulation 3 and includes amendments made to the Code of Practice from time to time;
“discharge pipe” means a pipe which conveys the discharges from a sanitary appliance or a floor trap;
“drainage system” means a network of underground pipes comprising drain-lines, branch drain-lines, fittings and inspection chambers for the conveyance of sewage within any premises to a sewerage system;
“fitting” means any apparatus together with its necessary appurtenances and connections attached to the sanitary plumbing system or drain-line of any premises;
“professional engineer” means a person registered under the Professional Engineers Act [Cap. 253];
“registered architect” means a person registered under the Architects Act [Cap. 12];
“sanitary appliance” includes a water-closet, urinal, bidet, wash basin, bath, sink and any other appliance fitted to a branch drain-line or a discharge pipe, connected to a drainage system;
“sanitary plumbing system” means a system of sanitary pipework above the ground comprising one or more discharge stacks, ventilating pipes, ventilating stacks and fittings for the conveyance of sewage from a building to a drainage system;
“sanitary works” include sanitary plumbing works and drainage works, and the fixing, alteration and repair of a sanitary appliance, and other works connected with sanitary plumbing, drainage or the fixing, altering and repair of a sanitary appliance.
Code of Practice on Sanitary Plumbing and Drainage System
3.  The Director may, from time to time, issue and amend a Code of Practice on Sanitary Plumbing and Drainage System setting out such standards, designs, requirements, procedures, and other details, pertaining to these Regulations and not inconsistent therewith, as he thinks fit.
Rain water and sullage water
4.  All sanitary works in any premises shall be carried out in accordance with the following requirements:
(a)all rain-water shall, where practicable, be separated from sewage, and all rain-water from roofs and open spaces and any overflow of water from storage tanks shall be diverted to a surface storm-water drain and away from any opening connected to a sewerage system;
(b)every roof shall be provided with a rain-water gutter so as to lead all rain-water therefrom away from any opening connected to a sewerage system;
(c)where there is an enclosed court or back-yard in the premises with no available surface outlet for rain-water, a sufficient area of the surface of the enclosed court or back-yard shall be paved so as to be able to lead any rain-water therefrom into a drain-line via a gully trap;
(d)no rain-water pipe leading down from the roof of a building shall be utilised as a ventilating stack or discharge stack;
(e)all sullage water from an area used for the washing of clothes or other things, a refuse chute or bin centre, and other like places of a building shall, where required by the Director, be discharged into a sewerage system;
(f)all sullage water from service stations and motor-workshops shall be discharged into a sewerage system via such oil and petrol interceptor as may be approved by the Director; and
(g)all backwash water from a swimming pool filter shall be discharged into a sewerage system.
Drainage system may connect to sewerage system
5.—(1)  The Director may, subject to such terms and conditions as he may impose, permit the owner of any premises to which a drainage system belongs or for the use of which it is maintained to connect the drainage system, at the owner's cost and expense, to a sewerage system, the control, supervision, maintenance and repair of which has been taken over by the Director under section 21 of the Act.
(2)  The owner shall make full compensation to the owners or occupiers of other premises for any damage caused to those other premises by connecting the drainage system to the sewerage system pursuant to paragraph (1) and for any loss suffered by those owners or occupiers.