Unlikely. My country have been through this (at a whole country level, not just a single city) for two years. It sped up desalination projects. People re-adjusted to the lack of water. Prices adjusted. Lots of water is wasted and very little water is actually being used for drinking. At the end, the rain came and it coincided with many desalination plants starting operations.

The prime minister suggesting evacuations is probably political. It is much easier to adjust to lack of water than to move your home/job somewhere else.