Surāmerayavagga

Vinayapiṭaka · Parivāra · Vol. 8 · Section 347

[347] A bhikkhu bathing within less than half a month commits two offenses (āpatti): while he is bathing, in the act itself there is an offense of wrong-doing (dukkaṭa); at the completion of the bath, an offense entailing expiation (pācittiya).

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 8 · Section 695 — Nahānavagga