The Lazio region has said that emergency measures to battle the prolonged dry spell could lead to staggered water supply shutdowns in neighbourhoods in the capital for eight hours daily, starting from this weekend.
Such a move could "seriously compromise sanitary hygiene standards in accommodation structures and restaurants in the capital, as well as in all public offices," Health Minister Beatrice Lorenzin said.
"But above all it could lead to grave problems in providing essential health services," she said.
The dry spell has deprived Italy of 20 billion cubic metres of water so far this year - the equivalent of Lake Como.
The region's rationing threat follows the decision to stop withdrawing water from Lake Bracciano near Rome because it had dropped to such a low level that it risked sparking an environmental disaster.
Acea, the utility firm which runs Rome's water system, has slammed the stop on using water from the lake as "unnecessary" and said earlier this week that the move left it no choice but to cut off supplies to residents.
A meeting between Acea and the region on Wednesday failed to resolve the crisis.
"We will continue to work to find a solution... we will look at all developments that arise, particularly with respect to the sanitary aspect," regional assessor Fabio Refrigeri said.
"We will find a solution shortly," he told journalists.
Ten regions across the country have called for a state of emergency to be declared after Italy suffered the second-driest spring in 60 years and rainfall in the first six months of the year was down 33 percent.