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Building safety

Defective Drainage

Building Defects

Defective drainage systems occur in various forms and to different extents in all types of buildings, irrespective of age.

Building owners should regularly inspect and maintain the drainage systems of their buildings in a safe and sound condition in order to help create a safe and healthy living environment.

Examples and signs of drainage defects

Leaking or broken drainage pipes at external wall
Leaking or broken drainage pipes at external wall
Rusty internal drainage pipes
Rusty internal drainage pipes
Unauthorised alteration of drainage system
Unauthorised alteration of drainage system

What should owners do?

Building owners, owners' corporations and building management and maintenance personnel are encouraged to conduct regular inspection on the drainage systems and sanitary fitments of their buildings to ensure that they are properly maintained and in working condition.

Check the following reference materials for details.

Building owners may carry out the repairs under the Minor Works Control System (MWCS). Minor works related to drainage systems:

What should owners do?
Minor Works for Drainage
Class I
Class II
Class III
Above ground - 2.30 3.23, 3.24
Underground 1.25, 1.26, 1.36 2.28, 2.29, 2.36 -

See also: Minor Works Control System - Drainage

If the drainage systems of a private building are found to be defective, inadequate or insanitary, Building Authority may serve an order under section 28 of the Buildings Ordinance (Cap.123) requiring the owners to carry out investigation and/or repairs within a certain period of time.

Owners should:

  • Appoint a competent contractor to investigate the drainage defects
  • Carry out necessary repairs or replacement works within the specified time.
  • For complicated cases, the order may require the appointment of an Authorized Person to investigate and submit remedial proposal for approval before the commencement of the remedial works.


Only in an emergency or in owner's default of an Order, Buildings Department would carry out works on his behalf and recover the cost of the works, plus supervision charge and surcharge from him.

Common questions

Building owners may apply in writing to Buildings Department stating the grounds for extension of time and a reasonable timetable of the works. However, Buildings Department normally will not accede to such request except in very special cases and you are therefore advised to comply with the order without delay.

Building owners may check against the records kept by the Land Registry as orders issued by Buildings Department would be registered in the Land Registry and discharged after the compliance. Alternatively, building owners may write to Buildings Department for enquiry.


Under Section 40(1B) of the Buildings Ordinance, any person who fails to comply with a statutory order served on him under Section 28(3) of the Ordinance shall be guilty of an offence and liable on conviction to:

Type Details of Penalty
Fail to comply with a statutory order
  • Maximum fine of Level 5 (HK $50,000 at present), and
  • Maximum imprisonment of one year
Failure to comply with the Order has continued
  • Further maximum fine of HK$5,000 for each subsequent day


Owners who obstruct the Owners Corporation in the execution of works to comply with BD's order without reasonable excuse may be prosecuted and liable on conviction to:

  • Maximum fine at level 3 (HK$10,000, at present) and
  • Imprisonment for 6 months.

Search contractor for repair and inspection of aboveground drainage system

  • The list of building professional only involves Authorized Person indicating their interest in providing services in the maintenance and repair of buildings and drainage to this department.
  • The list of Registered General Building Contractors only involves the contractors indicating their interest in providing services in the maintenance and repair of buildings and drainage to this department.