Why no facilities in the house? (3,4)
I believe the answer is:
how come
'why' is the definition.
(synonyms)
'no facilities in the house?' is the wordplay.
'no' becomes 'O' (resembles 0 - 'no' can mean 'zero').
'facilities' becomes 'wc' (water closet).
'in' means one lot of letters goes inside another.
'the house?' becomes 'home' (I've seen this before).
'o'+'wc'='owc'
'owc' going within 'home' is 'HOW COME?'.
(Other definitions for how come that I've seen before include "What's the reason" , "Explain why" .)