Residents of several areas of the capital, Tunis, have already complained of unannounced cuts to their mains supply at night since the start of the fasting month of Ramadan, when many stay up late.
"Years of drought and low water flow into reservoirs has impacted the country's water stocks, which have reached an unprecedented situation," the ministry said.
None of the country's major reservoirs is more than a third full, while some are at at less than 15 percent, threatening Tunisia's agricultural sector, which usually accounts for 10 percent of Gross Domestic Product.
Farmers' unions have voiced fears for the coming season, particularly as regards cereals. A poor domestic harvest would compound Tunisia's problems procuring sufficient flour in the face of skyrocketing international wheat prices since Russia's invasion of Ukraine early last year.
The Tunisian Federation for Agriculture and Fisheries said thousands of hectares of farmland risked being left fallow due to the lack of rain.
"This year's cereal season will be catastrophic -- there won't be a harvest," spokesman Anis Kharbech told Tunisian media. He said projected yields would not even be enough to provide seeds for next year's crop.
Scientists say that recurring heatwaves are a clear marker of human-caused global warming, and that droughts worldwide are set to become more frequent, longer and more intense.
Along with the quotas, Tunisian authorities have started cutting off drinking water at night in areas of the capital and other cities, including Hammamet, Sousse, Monastir and Sfax.
Tunisian dams recorded a decrease in capacity of around of 1 billion cubic meters due to scarcity of rain from September 2022 to mid-March 2023, Hamadi Habib, a senior official in the agriculture ministry, said.
The Sidi Salem Dam in the north of the country, a key provider of drinking water to several regions, has declined to only 16 percent of its maximum capacity of 580 million cubic meters, official figures showed.
This report was sourced from Reuters and Agence France-Presse.