"These people need water."
Translation:Tito lidé potřebují vodu.
"tito lidi" should also be correct. lidé and lidi are both plural (nom) of člověk, or am i wrong?
"Lidi" is colloquial and therefore considered as Standard Czech. It's also mentioned in the link that you posted (the first sentence below the table with declensions). For some reason, it's missing in the table.