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Water Storage Tanks


All MCSTs and building owners have to be responsible for the proper maintenance and security of their water service installations, including water storage tanks. This is to ensure that water conveyed through them is fit and safe for drinking at all times. If not properly maintained, it can be a potential source of contamination.

It is the legal responsibility of MCSTs and building owners to keep proper annual water tank certification records, closely monitor the deadline and engage a Licensed Plumber early. Failure to complete and submit the annual certification in a timely manner before the deadline is an offence under the Public Utilities (Water Supply) Regulations. The penalty for late certification is a fine not exceeding $10,000 or imprisonment for a term not exceeding 12 months or both.

PUB issue reminder emails to assist MCSTs and building owners with the monitoring of the annual certification. Notwithstanding, you should NOT wait for PUB’s reminder emails before engaging a Licensed Plumber to carry out the work. If you do not receive our reminders and would like to enquire on the certification deadline or update your email address, please click here.

The maintenance and security requirements of water storage tanks are stipulated in the Public Utilities (Water Supply) Regulations and the Singapore Standard SS 636: Code of Practice for Water Services.

PUB conducts spot checks to ensure that the water storage tanks are properly maintained and secured in accordance with the stipulated requirements. The checks are conducted by a group of Qualified Checkers (QCs) employed by our Contractors (One Centum Pte Ltd and Mei De Engineering Pte Ltd). We seek your kind cooperation to make the necessary arrangements with our Contractors if the water storage tanks at your premises have been scheduled for a joint inspection.​

Inspection and Certification of Water Storage Tanks

Any person responsible for the maintenance of any part of a water service installation having a water storage tank shall engage, at least once every 12 months, a licensed plumber to inspect, and where necessary to clean and disinfect, and certify the water storage tank.


  • the water storage tank is fit and safe for the storage of water for human consumption
  • the water contained in the water storage tank is free from contamination or pollution
  • water samples taken from the water storage tanks pass the appropriate chemical and bacteriological examinations
  • the water storage tank is properly maintained
  • there is no leakage and no likelihood of leakage in the water service installation, including the water storage tank


The mandatory annual inspection and certification of water storage tanks does not apply to landed residential properties, clustered private housings with water storage tank after the sub-meter etc. The premises owners are responsible to engage a licensed plumber to clean and maintain the water storage tank regularly to ensure that the water is fit and safe for human consumption.

Water Sample Testing

Water samples taken from the water storage tanks is sent to a Singapore Accreditation Council-SINGLAS accredited laboratory for testing of potable water quality to pass the appropriate chemical and bacteriological examinations. Only satisfactory test reports from laboratories accredited by Singapore Accreditation Council-SINGLAS will be accepted. The minimum parameters to be tested and the corresponding typical values they must comply with are shown in table below.

Physical, Chemical & Bacteriological CharacteristicsTypical Water Quality Values to be complied with
Physical Analysis Parameters
Colour (Hazen Unit)<5
Turbidity (NTU)<5
pH Value7.0 – 9.0
Conductivity (umhos/cm)80 – 550
Chemical Analysis Parameters
Residual Chlorine (as mg/l CL2) <2.0
Iron (as mg/l Fe)<0.04
Bacteriological Characteristics
Total Colony Count (cfu/ml, 35oC, 48 hrs) <500
E.Coli (cfu/100ml, 35oC, 24 hrs) <1
Maintaining Water Pipes & Tanks

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