The Law Code of Yājñavalkya 3.1.40

3.1.40

tac codakadānam itthaṃ kartavyam | sapiṇḍāḥ samānodakāś ca maunino bhūtvā pretasya nāmagotre uccārya amukanāmā preto 'mukagotras tṛpyatv iti sakṛd evodakaṃ prasiñceyuḥ trir vā, triḥ prasekaṃ kuryuḥ pretas tṛpyatv iti iti pracetasaḥ smaraṇāt | pratidinam añjalivṛddhis tu pratipāditaiva | tathā ayam api viśeṣas tenaivoktaḥ |

And that offering of water is to be done in this manner: kinsmen connected by funeral cake and those connected by water libation, remaining silent, reciting the name and gotra of the deceased, saying: "May the deceased named so-and-so, of such-and-such gotra, be gratified," should pour out water only once, or thrice, according to the traditional text of Pracetas: "They should pour out water thrice, saying, 'May the deceased be gratified.'" The daily increase of handfuls of water has already been explained. Likewise, this distinction also was stated by the very same [author]: