The authors agree that this surname would derive from the names of localities characterized by the presence or abundance of water. E. Rossoni notes that the main clusters are found in Liguria and Sicily, with variants such as Lacqua documented in the Turin area, in Acqui Terme and in Nizza Monferrato, in Piedmont.

F. Miranda broadens the etymological hypotheses and indicates that the surname could derive from place names containing the word acqua, such as Acquedolci, Acqua Nocelle or Acquafredda, or else be linked to the trade of the first bearer, a distributor or seller of water (acquaiolo). Miranda also records a presence in Lombardy and Lazio, as well as cores in the Enna area, in Sicily, where it is known in localities such as Gagliano Castelferrato, Agira and Regalbuto.