ποριστέον
From LSJ
τὸ ἐγδοχῖον τοῦ ὕδατος καὶ τὰ ἐν τῆι πόλει ὑδραγώγια → the water reservoir and the conduits in the city (or on the acropolis)
English (LSJ)
one must provide, Epicur.Fr. 481, Chrysipp.Stoic.3.172, Iamb.in Nic.p.58P.
Greek (Liddell-Scott)
ποριστέον: ῥημ. ἐπίθ., δεῖ πορίζειν, Σχόλ. εἰς Εὐρ. Ὀρ. 671.