Rujeib council head Ahmad Dweikat said the water pumped to his village had been lowered from 5,000 cubic meters to 2,500 cubic meters without prior notice three weeks ago.
The nearby villages of Azmut, Salim, and Deir Al-Hatab have undergone the same reduction, he said.
The four villages have a combined population of 16,000, and several homes on hilltops have not had a supply of water for three weeks. As a result, residents are purchasing water from delivery tanks that cost up to 300 shekels ($95) for 10 cubic meters.
A spokesman for Israel's Civil Administration said the same amount of water was being pumped to the Rujeib
Residents filed a complaint three weeks ago and again on Wednesday that the water supply was not reaching them, he said.
A representative from Israel's Mekorot water company was sent out and determined the water was being illegally diverted, he added.