Korean Grammar Dictionary

-러 【물을 길 [ edit | delete | edit examples ]
연결어미 Connective ending (연결어미 Connective ending)
『 』
Purposive -(으)러 for the purpose of ...-ing; in order to ... (usually with verbs of motion). Stems ending in vowels and -ㄹ- take -러, all others take -으러.

물을 길 (학마을 )
[The girls went to the well] to draw water. (Here on 긷다, 길어, 길러 but one would expect 길으러.)