Drinking

Respected scholars, as-salamu `alaykum. I come home thirsty and I drink a cup of water in one breath. Is this permissible? jazaka Allahu khayran

Asalaulikum, Please detail the Islamic etiquettes of eating? I know that its good only to eat when hungry and to fill in 1/3 for eating, 1/3 for water and 1/3 for leaving space for your body to breath.