Who bears the maintenance costs of common areas in a rented residential complex, given that it was not mentioned in the contract who bears them, and knowing that they are paid whether the apartment is rented or not? And is Zakat obligatory on the entire rental income given as charity?

Summary of the Answer:

Zakat is obligatory on apartment rental income if a year has passed over it and it reaches the nisab (minimum threshold) by itself or when combined with other assets. The landlord is responsible for the maintenance costs of the rented property. Any amount spent from the rent before the year has passed is not subject to Zakat.