Qarah Su Rural District () is in the Central District of Maku County, West Azerbaijan province, Iran. Its capital is the village of Dim Qeshlaq-e Olya.
Qarah Su Rural District was established in the Central District in 2007.
At the time of the 2011 census, the rural district's population was 6,955 inhabitants in 1,411 households. The 2016 census measured the population of the rural district as 6,012 in 1,372 households. The most populous of its 24 villages was Dim Qeshlaq-e Olya, with 1,015 people.