Water, water everywhere, and not a drop to drink

I was watching an episode of Stargate Atlantis in which someone comments that 'it takes forever to get things from Earth that aren't vital to the success of the mission'.

Elsewhere in the episode, there are several scenes in the cafeteria:

From Stargate Atlantis 3:17 "Sunday"

Is it vital to the mission that they have Evian water to drink?

This is Atlantis:

Admittedly, the water surrounding it is salt water. But surely an ultra-high-tech city like this would have a desalination plant?*

Or, if they really want spring water, the mainland isn't too far away.**

I can easily suspend my disbelief to accept that they have found the lost city of Altantis in the Pegasus galaxy, and that they have a ship with hyperspace drives that they can use to get there.

But importing bottled water 3 million light years? That's unbelievable.

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* Having restarted watching the series - it is in fact established in the first episode that they do have a desalination plant.

** A 25 minute flight