Nanoparticles are the tiny materials with size ranged from 1 nm to 100 nm. Classification of nanoparticles could be done in different classes depending on their properties, shapes or sizes. Certain difficulties in classification of nanoparticles arise because the shape, size and structure of nanoparticles determine their properties. These mutual dependencies cause the careful approach in classification of nanoparticles and direct to the more suitable classification based on their application. Utilization of nanoparticles could be applied in reaching commercial and/or domestic goals including medical applications, energy-based research, environmental and applications connected with sustainable development. Nanoparticles as complex molecules also are not of simple structure. They are composed of three layers: surface layer, shell layer and of the core. The complexity of nanoparticles inevitably leads to the question of their influence on environment and possible toxicity i.e. the risks of their utilization. Risks of the nanoparticles utilization in environment should be assessed after truly understanding their mobility, reactivity, eco toxicity and persistency. Especially the exposure of water, ground water and soil exposed to the nanoparticles’ possible negative influences should be researched carefully. In this paper the effort for assessment of nanoparticles contribution and possible risks was done. The model for risk of nanotechnologies utilization in water use is developed and assessed. The model for risk assessment was developed on the base of probability of undesired influences of nanoparticles utilized in process of water use. The process of water use for human needs satisfaction includes the water supply, water consumption and water treatment. The risk of nanotechnology utilization includes the all segments of the process.