A decree signed by the environment and housing ministers would increase rates by less than 1%, according to the latter.
As of Friday, some areas of the capital city regained service, while President Salvador Sánchez requested all public institutions support water utility ANDA in restoring service to the affected areas.
The southern Brazilian state is investing some US$26mn in the metropolitan region of state capital Porto Alegre.
The bank and the city's water utility EMAPAG signed a US$30mn loan agreement that will finance rain water drainage works, which are expected to benefit 500,000 residents.
The project will benefit 90,000 residents of the Brazilian state.
Some US$65mn was invested in beach resorts in the southern Brazilian state.
Most of the investment will come from the federal government.
Local authorities expect to restore full service by Friday. Eyewitnesses said the perpetrators were "heavily armed."