The master's thesis deals with the subject of disposal and treatment of wastewaters from settlements near the spring of Dobličica River. These settlements are Grič pri Dobličah, Dobliče, Blatnik pri Črnomlju, and Jerneja vas. To this day, the area does not have appropriate arrangements for disposal and treatment of wastewaters in accordance with current legislation, which explicitly deals with smaller dispersed settlements. New arrangements are necessary because these settlements are partially situated in the water protection area of the water resource Dobličica. That is the main water resource in the municipality of Črnomelj; it has the highest flow and it is used to supply water to the majority of inhabitants. The purpose of this master's thesis is to identify the most appropriate solution for disposal and treatment of wastewaters with regards to necessary technology and investment. Three conceptual solutions for the sewer system and associated wastewater treatment plants are presented; required technology and investments are compared. The most appropriate conceptual solution is determined.