The 'colossal wave' in Tempoross should fill up your bucket with water (regardless of being tethered or not) : r/2007scape
Demon Slayer Quest Guide - Global RuneScape
Water-filled gourd vial | Old School RuneScape Wiki | Fandom
Fill a bucket from the pump north of Falador west Bank - RuneNation - An OSRS PvM Clan for Learner Discord Raids, PKing, PVM, Bossing, News, Merchanting, Quest Help