Can't get out of the city, out of the question. It has been tried... we are tied down.

And, everyone should have water stockpiled... and be ready to collect rain...
The solar still is just a way to get enough water to live during a dry time, if your water is exhausted. It will slow the rate of consumption of stored water all the time.

A large still, especially of you rigged up a still with a Fresnel lens, could produce plenty of clean water.