Where new water-carrying services have to be so routed that leakage could affect slopes, Chapter 9 of Geotechnical Manual for Slopes (GCO, 1984) recommends measures to safeguard against the effect of leakage. These include taking into account the effects of possible water leakage in assessing the stability of the slopes, or enclosing the water-carrying services in ducting systems. Laying the water-carrying services on or above ground is another alternative.Ducting to water-carrying services should be provided with proper drains. Standard drawings for ducting of water mains are available on the web site of the Water Supplies Department. Drains from ducting to sewers should not be discharged to open channels and natural streams where possible to avoid environmental nuisance. To facilitate regular inspection for discharge from ducting systems as recommended in GCO (1984), inspection chambers with safe access should be provided. Regular checks of the ducting system should be carried out to detect any flow in and leakage from it.For slopes that could be affected by leakage from water-carrying services, raking drains could be installed to reduce the impact of leakage. Reference should be made to GEO Report No. 56 (Wong et al, 1999) for guidance on use of prescriptive raking drains in this regard.