Gobhilagrihyasutra 1.4.6

1.4.6

sakṛd apo ninīya caturdhā baliṃ nidadhyāt, sakṛd antataḥ pariṣiñcet;

Let him pour out water once, and put down Balis in four places, and finally sprinkle once (water on the four Balis).