The report describes an innovative approach to assess the water protection of bedrock. Groundwater movement modeling experiments are used in the LAMO environment of the regional hydrogeological model, for each node of the active zone of the model. By interpreting the time required for water-soluble contamination from the terrain to reach the nearest bedrock water horizon, bedrock water protection is determined. As a result of the development of the stage, the first underground water protection map of the bedrock water horizon for the territory of Latvia has been created, the data tables of LAMO4 nodes created in the previous stage have been supplemented with the obtained data.