SOLVED. Middle Grade Fantasy Adventure: Mixed tap water and some seriously weird stuff in the sewers of London. [s]

[Diarmuid]

novel i read back in primary school, specifically sometime between 2015 and 2018.
it was about a girl who moved from chicago ( i distinctly remember the beginning mentioning she came from chicago, since my dad used to live there so i got excited when i saw it was mentioned and told him about it ) to london. she’s told about how in the UK, they have separate knobs for hot and cold water and that she should never turn both on at the same time. she thinks it’s weird and inconvenient, so she ignores the warning and does just that. but then instead of water, this weird goopy stuff comes out. then more stuff happens and she goes on this adventure in the sewers and fights these weird grey fellas who are like a cult or something in the sewers.

[Capn]

I've recently started a list of books set (even just partially) in Sewers:
https://www.goodreads.com/list/show/1...

I don't think it's there yet, though.

Anything on the "Under London" list? https://www.goodreads.com/list/show/7...

[Diarmuid]

thanks for the help! but no, under london seems to be mostly adult novels and this was a MG/children's book.

[Rainbowheart]

Does anything on the Underground Cities list look familiar?

[Diarmuid]

no, but i finally found it through google books! it's Hyacinth and the Secrets Beneath

[Rainbowheart]

Awesome, glad you found it!

[Capn]

Nice work!! :)