Hydrothermal carbonization is a thermal conversion method of treating biomass or waste which is carried out in an aqueous environment under temperature and autogenous pressure. Although the solid product, hydrochar, can be successfully used as an energy source, biofertilizer or potential adsorber, post-processing water - a major product of the process - is incredibly difficult to utilize. This is mainly due to the content of numerous organic compounds (e.g. phenolic, furan, alkene, aromatic and aldehyde compounds) and short-chain organic acids (e.g. acetic acid, benzenoacetic acid, propionic acid, butanoic acid). Therefore, an adequate method of post-processing water utilization is required, such as the distillation process. The main objective of this work is to investigate the influence of vacuum depth on the properties of liquid products. The chemical and physical indicators were determined to confirm the validity of this treatment method and to choose the optimal distillation conditions. The following parameters were determined: COD, TOC, ammonium nitrogen content, total nitrogen Kjeldaha content, phosphorus, magnesium, calcium, selected heavy metals content and phenol index. Promising results have been achieved: distillation led to a reduction in the content of heavy metals and a significant reduction in other parameters. In addition, the effect of the vacuum depth on this parameter was observed.