Zechariah 14:8 (WEB)
It will happen in that day that living waters will go out from Jerusalem, half of them toward the eastern sea, and half of them toward the western sea. It will be so in summer and in winter.
Catechism · 1
“Thus the Spirit is also personally the living water welling up from Christ crucified as its source and welling up in us to eternal life.” — Catechism footnote: Cf. Jn 4:10-14; 738; Ex 17:1-6; Isa 55:1; Zech 14:8; 1 Cor 10:4; Rev 21:6; 22:17.