The Law Code of Yājñavalkya 3.1.32

3.1.32

saptamād divasād arvāg daśamadivasād vā jñātayḥ samānagotrāḥ sapiṇḍāḥ samānodakāś ca apa naḥ śośucad agham (RV 1.97.1–8) ity anena mantreṇa dakṣiṇāmukhā apo 'bhyupanayanti | abhyupagamanena tatprayojanabhūtodakadānaviśiṣṭam abhyupagamanaṃ lakṣyate, evaṃ mātāmahācāryeṣv ity anantaram udakadānasyātideśadarśanāt | etac cāyugmāsu tithiṣu kāryam, prathamatṛtīyapañcamasaptamanavameṣūdakakriyā (GDh 14.40) iti gautamasmaraṇāt | etac ca snānānantaraṃ kāryaṃ | śarīram agnau saṃyojyānavekṣamāṇā apo 'bhyupayanti iti śātātapasmaraṇāt | tathā pracetasāpy atra viśeṣo darśitaḥ: pretasya bāndhavā yathāvṛddham udakam avatīrya noddharṣayeyur udakānte prasiñceyur apasavyayajñopavītavāsaso dakṣiṇābhimukhā brāhmaṇasyodaṅmukhāḥ pratyaṅmukhāś ca rājanyavaiśyayoḥ iti | smṛtyantare tu yāvanty āśaucadināni tāvad udakadānasyāvṛttir uktā | yathāha viṣṇuḥ: yāvad āśaucaṃ tāvat pretasyodakaṃ piṇḍaṃ ca dadyuḥ (ViDh 19.13) iti || tathā ca pracetasāpy uktam |

Prior to the seventh day, or from the tenth day, relatives belonging to the same gotra—sapiṇḍas and samānodakas—facing south, approach the water with the mantra: 'May our sin burn away' (RV 1.97.1–8). By 'approaching' [the water], what is indicated is the act of approaching characterized by the water offering which is its purpose, since immediately following, an extension of the water offering is seen in the words: 'So for maternal grandfathers and teachers.' And this is to be done on uneven lunar days, in accordance with the Smṛti of Gautama: 'The water rite is performed on the first, third, fifth, seventh, and ninth [days]' (GDh 14.40). Moreover, this should be done after bathing, in accordance with the Smṛti of Śātātapa: 'Having consigned the body to the fire, not looking back, they approach the water.' Likewise, an additional detail has been shown in this matter by Pracetas: 'Relatives of the deceased, having entered the water in order of age, should not sprinkle each other with water; on the edge of the water they should pour it, with sacred thread and garment turned to the right side, facing south for a Brahmin, facing north and facing west for a Kshatriya and a Vaishya.' In another Smṛti, however, repetition of the water offering is enjoined for as many days as there is ritual impurity. As Viṣṇu says: 'As long as there is ritual impurity, so long should they offer water and a piṇḍa for the deceased' (ViDh 19.13). And likewise, it has been stated by Pracetas as well: