“The whole house was constantly in a state of inundation, under the discipline of mops and brooms and scrubbing brushes." What does inundation mean?
There are two meanings: an overwhelming amount, and flooding.
There are two definitions to "inundation":
an overwhelming amount (for instance, call centres are usually inundated with calls, which is why they so often say they are experiencing high call volume), and
a flood or flooding.
This could be a play on words, where both meanings can apply and depending on which (or both at once) you use changes the meaning of the sentence.