In our paper, we presented the results of numerical simulations dealing with the production of water from the nucleus of a hypothetical dynamically new comet. The simulations were performed using empirical equation based on the results of laboratory experiments performed in vacuum using ice agglomerates. We presented also the results obtained using simple, popular approach. The model nucleus is a prolate ellipsoid of rough surface. The results were compared with the observed production of water from the nucleus of comet C/2012 K1 PanSTARRS. Our simulations indicate, that the observed production of water can be reproduced without assuming the presence of highly volatile ices when the dust may slide down the slopes and the thermal conductivity of the nucleus is very low.