(35) CHAPTER. If a property is equally owned by two partners, its Zakat is to be paid as a whole, and each partner is to pay the same amount.
Narrated Anas: Abu Bakr wrote to me what Allah's Apostle has made compulsory (regarding Zakat) and this was mentioned in it: If a property is equally owned by two partners, they should pay the combined Zakat and it will be considered that both of them have paid their Zakat equally.
Authentic