Bolivian President Evo Morales has declared a national emergency over a lack of water caused by a severe and prolonged drought.
Morales said on Monday that national and local governments are authorised to use state resources to attack the problem.
Much of the high-altitude capital already receives water for just three hours every three days because reservoirs serving the city are nearly dry.
Morales said Bolivians "have to be prepared for the worst".
The El Nino weather phenomenon in the Pacific has caused or exacerbated the drought, which has battered farms and cattle ranches.
The country's weather service says no rains are expected before early December.
On Sunday, authorities declared water rationing in La Paz to be a permanent measure as the drought in Bolivia worsens.
The three main dams that supply water to the city are almost dry.
The main Ajuan Khota dam is at one percent of capacity, while the other two dams are averaging eight percent capacity.
This has led to water cuts in some neighbourhoods for the first time. The Corque municipality has been particularly hard hit, according to a report from the Pan American Health Organisation, and 70 percent of the population lacks drinking water.
Protests
Across La Paz, residents have seen their taps dry up for 60 hours at a time, followed by 12-hour periods to replenish their supplies.
Morales sacked his top state water authorities and apologised for extended water rationing in the capital.
The neighbouring city of El Alto is also concerned about the lack of water. A week of protests by frustrated residents has escalated tensions.
On Thursday, leaders of the Federation of Town Councils - Fejuve - held officials and water authorities hostage after the Minister of Environment and Water, Alexandra Moreira, failed to turn up for a meeting to report on a water supply project in the city of El Alto.
Police were eventually called to release the hostages, including Ruben Mendez, Bolivia's deputy water minister.
Riots over water have broken out in Bolivia before. Those which took place in 2004 resulted in the control of water being handed over from private companies to the state.
In recent decades, Bolivian glaciers have shrunk drastically and impacted the lives of millions who depend on glacier melt for water.
