Although similar looking, and both have the "water at left" 氵 radical...
Yuyu (湯々)
湯 meaning: hot water
Unique radicals:
日 - sun
勿 - not
Gatagata (潟々)
潟 meaning: lagoon
Unique radicals:
臼 - mortar
勹 - wrapping
灬 - fire
That these two Kanji look similar is why Jobko attends Gatagata and not Yuyu, since she's from America and she wrote down the wrong kanji when applying for schools.
YuyuThe name of their school.GatagataThe name of their school.