Zam-zam has been flowing from the Ka’aba for over 4000 years. Samples taken from all water sources in the world contain some germs in it. Through studies by Doctor Yahya Koshak (expert on Zam-zam) it has been proven that Zam-zam does not contain any contaminants. It is an established scientific fact that pools or water wells tend to grow vegetation such as algae– especially in warm climates. Amazingly this is not the case in the well of Zam-zam. It has remained free from biological contaminations.