"Do you have clean water?"

Translation: Czy macie czystą wodę?

[miller032]

Why is it wode rather than woda here?

[Jellei]

The verb "mieć" (to have) needs Accusative, which is "wodę".

[JonasEvant2.0]

Is "Czy ma pan czystą wodę?" acceptable? (or with "panie" for that matter)

[Jellei]

Yes, of course. But as it's still the case with many sentences, the formal versions were missing from the list of accepted answers. Added now.