"The biggest problem and concern now on Everest is human waste," says former Nepal Mountaineering president Ang Tshering.
The revelations come after a horror season on the mountain. Last month, 11 climbers were killed within two weeks as queues of hundreds of people formed in what was being called the "death zone".
Now campaigners say the amount of human waste on the mountain is threatening local drinking water.
Western Washington University Professor of environmental science John All, who visited the iconic mountain for research, says eight out of 10 sherpas became sick during his expedition due to bad water.
It is also impossible to tell how much rubbish had been left on the mountain, AP reports.
"Everest is our god and it was very sad to see our god so dirty," local climber Nima Doma says.
"How can people just toss their trash on such a sacred place?" she told AP.
The Nepalese government says it's devising a plan for climbers to pay a $4000 deposit before going up the mountain.
Climbers' equipment and gear would be tagged, and if they returned without their items, they may not be refunded, AP reports.