台所 and 浴室: kitchens and bathrooms
Distinguish a room's purpose from where an action currently occurs.
A space for cooking
台所 (だいどころ) means kitchen. 「台所で夕食を作っています」 describes preparing dinner in the kitchen.
「台所に水があります」 locates water in the kitchen. The presence of water and an ongoing cooking action are different information.
A space for bathing
浴室 (よくしつ) means bathroom or bathing room. 「浴室を掃除しました」 says the bathroom was cleaned.
「浴室の窓を開けました」 means opening the bathroom window. The direct target of opening is 窓, not the whole 浴室.
Action order and intended use
「台所を片付けてから、浴室を掃除します」 places tidying the kitchen before cleaning the bathroom. Do not swap the action locations.
「台所用の布」 and 「浴室用の布」 identify cloths for kitchen and bathroom use respectively. Intended use does not establish where the cloths currently are.
What was opened in 「浴室の窓を開けました」?
Show the answer and why
The bathroom window. The noun before の identifies the window's location.