The result of a breakage of a buried water pipe is the water movement in soil, which can cause that fine soil particles are washed out from the solid matrix and transported through pores (suffosion process IntroductionDepressions or holes creating on the soil surface as a result of suffosion can be very dangerous, especially in urban areas. It is widely known that the most hazardous phenomena of this kind relate to water-engineering structures [1,2,3]. It stems from the fact that failures and damages of pipes occur in water, sewage and storm water systems all over the world during their operation [4,5,6]. Even the high-tech methods of pipes condition assessment do not enable to prevent leakages occurrence, because of their random character and multiplicity of their reasons [7,8,9]. Still insufficient knowledge about them [10] is caused by many different, both static (pipe and soil parameters) and dynamic (hydraulic working conditions), factors [11,12,13,14,15]. Creation of suffosion holes is a phenomenon specially typical and onerous for water supply systems of a high intensity rate placed in internally unstable soils. The result of a breakage of a buried water pipe is the water movement in soil, which can cause that fine soil particles are washed out from the solid matrix and transported through pores (suffosion process) [16,17,18,19,20,21]. As a result, depressions or holes can form on the soil surface. Holes creating on the soil surface by water outflowing after a failure of a buried pipeline (suffosion holes), are in different shapes and sizes.Recognition of factors influencing holes shapes and sizes would facilitate the prevention of hazardous suffosion effects connected with failures of water distribution systems. In the range of the presented article, the influence of pressure head in a water pipe on dimensions of suffosion holes was analysed. The basis of the analysis was results of laboratory investigations of the controlled leakage from a buried water pipe.