Private Slope Maintenance and Repair

Lack of maintenance is a major contributory factor to many landslides in Hong Kong. Poorly maintained slopes, even those which were designed and constructed to adequate engineering standards, can deteriorate to the point where they may fail and endanger life and property. To reduce the probability of landslides, owners should maintain their slopes regularly.

1. What is "Private Slopes"?Expand

"Private Slopes" refer to slopes, retaining walls and landslide risk mitigation facilities (hereafter referred to as "slopes") with the maintenance responsibility resting with the owners of private properties or parties. The Geotechnical Engineering Office (GEO) of the Civil Engineering and Development Department (CEDD) has registered about 60,000 man-made slopes in the Slope Catalogue. One third of which (i.e. about 20,000) are of private responsibility. The public can retrieve the slope information from the "Slope Information System" of the GEO.

2. Maintenance responsibility of slopesExpand

The maintenance responsibility of slopes is determined based on the ownership of land, which is conferred by a lease document issued by the Lands Department, such as a government lease or conditions of grant, conditions of sale, and conditions of exchange. Owners may also be liable under specific lease conditions for the maintenance of slopes adjoining their lot. The public can access to these lease documents and records of owners at the Land Registry, or make quick reference of the maintenance responsibility through the "Slope Maintenance Responsibility Information System (SMRIS)" maintained by the Lands Department. Owners should seek professional advice from lawyers or estate surveyors if they have any doubt on maintenance responsibilities of the slopes.

3. Legislations related to slope maintenance and repairExpand
  1. Cap. 334 Building Management Ordinance

    Section 44(1)(b) of the Building Management Ordinance (BMO) requires corporations to observe and follow the safety standards and code of practice issued by the Secretary for Home Affairs, such as "The Code of Practice for Building Management and Maintenance". The Code of Practice requires that any slope or retaining wall for which a private owner is responsible shall be maintained in a state of good condition in accordance with "Geoguide 5 - Guide to Slope Maintenance" published by the GEO. A failure on the part of any person to observe any Code of Practice issued under Section 44(1) of the BMO shall not of itself render that person liable to criminal proceedings of any kind but any such failure may, in any proceedings, whether civil or criminal including proceedings for an offence under the BMO, be relied upon as tending to establish or to negative any liability which is in question in those proceedings.

  2. Cap. 123 Buildings Ordinance

    When a slope is found to be dangerous or liable to become dangerous, the Buildings Department (BD) will serve a Dangerous Hillside Order (DHO), in accordance with Section 27A of the Building Ordinance, requiring the slope owners to investigate and if necessary rectify the situation. DHOs are usually issued under the following circumstances:
    • when there is prima facie evidence that a private slope is dangerous or liable to become dangerous identified in the "safety screening" studies under the ongoing "Landslip Prevention and Mitigation Programme" of the Government;
    • a landslide has occurred or significant signs of distress are found in a private slope on which geotechnical study and/or extensive repair works are required to rectify its long term stability.
    At the time when the BD issues a DHO, such Order will be registered against the related land title in the Land Registry until it is complied with. As the owner bears the legal responsibility, this may affect the owner's plan to undergo any transaction of the concerned property.
4. What you need to know as a Slope OwnerExpand
  1. The recommendation of the government on slope maintenance

    The "Geoguide 5 - Guide to Slope Maintenance" produced by GEO, deals basically with the maintenance inspections and maintenance works necessary to keep in good condition of the well-designed and properly constructed slopes. The maintenance inspections and works recommended in this Geoguide can also reduce the probability of instability of slopes which are not up to the current geotechnical standards for design and construction.

    The Geoguide 5 recommends owners to arrange for Routine Maintenance Inspections (RMI) at least once a year to establish the need for Routine Maintenance Works (RMW), and to carry out Engineer Inspections (EI) for Maintenance at least once every 5 years. During RMI, particular note should be taken of anything considered to be unusual. If there are any signs of abnormality (please refer to "Keep Your Slope Safe" leaflet), owner should then appoint a professionally-qualified geotechnical engineer without delay to undertake an immediate EI for Maintenance, and to recommend any necessary actions.

    Leakage from buried water-carrying services that may affect the stability of slopes may not be visible on the surface. Therefore, owners should also arrange for regular checks and maintenance of buried water-carrying services in accordance with the "Code of Practice on Monitoring and Maintenance of Water-Carrying Services Affecting Slopes", which can be downloaded from the website of the Development Bureau (

    The GEO has produced "Layman's Guide to Slope Maintenance", an abridged version of the "Geoguide 5 - Guide to Slope Maintenance", to assist private owners to understand and discharge their duties on slope maintenance. The leaflet "Keep Your Slope Safe" also contained information on regular slope maintenance for public to make reference.

  2. The Requirement of Personnel for the inspection

    Since the primary purpose of RMI is to establish the need for basic maintenance works of man-made items on slopes. The general items that involve clearance and removal under the Routine Maintenance Works, such as clearance of accumulated debris from drainage channels and slope surface, unblocking of weepholes, could be carried out by any responsible person. However, if the required Routine Maintenance Works involved the repairing works, such as repair or replacement of cracked or damaged slope surface cover, or repair the missing pointing in masonry wall, the owner shall arrange minor works contractor for the repair works under the Minor Works Control System. Details are available at BD website. Public could also make enquiry through their hotline 2626 1616 (handled by 1823).

    An Engineer Inspection for Maintenance should be carried out by a professionally-qualified geotechnical engineer in Hong Kong, such as Registered Professional Engineer (Geotechnical) (RPE(G)). Information of the RPE(G) can be obtained from the Engineers Registration Board. Owners are recommended to invite not less than three engineers to provide quotation for the required inspection services.

  3. Maintenance manual

    A maintenance manual documents the general information related to the slope and retaining wall, the construction of the man-made facilities, and the information of the required maintenance inspection items etc. For properly designed slopes that are constructed with the approval and consent of Building Authority, the engineer should also be responsible to prepare a maintenance manual as part of his design services in order to assist owners to carry out the slope maintenance appropriately. The owner should make reference of the maintenance manual for routine maintenance inspection and Engineer Inspection for maintenance. However, some slopes could have been formed for years, the design and construction of which might not meet the suitable engineering standards, and therefore was not equipped with a maintenance manual. Under this circumstance, the owner should immediately acquire a service for Engineer Inspection for Maintenance. The engineer would conduct thorough check of the design and construction records and other relevant information for the preparation of the maintenance manual. If there is not any record of previous stability assessment of the concerned slope, the engineer should recommend for such assessment. The owner should be aware of whether stability assessment has been conducted for the slopes being maintained, so as to determine whether or not the concerned slopes meet current safety standard. Generally speaking, slopes that do not meet current safety standard will have a higher risk of landslide. For enquiries of slope maintenance and repair, owners can seek the advice from the Community Advisory Unit of the GEO (Tel 2760 5800).

  4. Maintenance records

    Maintenance manuals, all records of maintenance inspections and subsequent maintenance works should be kept by the owner or the appointed agent, or by the party required to maintain land. In practice, it is advisable to keep duplicate copies of all records and to store them in separate locations. Comprehensive and accurate record keeping is important for good maintenance management.