صحيح البخاري Sahih Bukhari كتاب الزكاة The Book of Zakat
بَابُ مَا كَانَ مِنْ خَلِيطَيْنِ فَإِنَّهُمَا يَتَرَاجَعَانِ بَيْنَهُمَا بِالسَّوِيَّةِ:

(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.

1 hadith
Hadith 1451
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ , قَالَ : حَدَّثَنِي أَبِي , قَالَ : حَدَّثَنِي ثُمَامَةُ ، أَنَّ أَنَسًا حَدَّثَهُ ، " أَنَّ أَبَا بَكْرٍ رَضِيَ اللَّهُ عَنْهُ كَتَبَ لَهُ الَّتِي فَرَضَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ ، وَمَا كَانَ مِنْ خَلِيطَيْنِ فَإِنَّهُمَا يَتَرَاجَعَانِ بَيْنَهُمَا بِالسَّوِيَّةِ " .
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.
Hadith Reference Sahih Bukhari / The Book of Zakat / Hadith: 1451
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة