Villagers say Cheng could have been a millionaire if he accepted money and gifts from the beneficiaries of the water he finds. But Cheng refuses to accept anything and donates almost all his savings and monthly pension to the villagers.

Despite his ill treatment, he carried on with his work until 1975 when his health collapsed and he decided to return to his hometown.

After he recovered, he started helping his parents in the fields, and he cultivated dozens of hectares of barren mountain land into the most productive farmland in the village.

He also started looking for water for the local people.

Familiar with the geological conditions of the Liuwanda mountain range in Yulin, Chen can tell whether there is water underground and how deep the well would be by tasting the local soil.

Helping the villagers look for water has now become his main occupation. In the past 39 years, he has helped dig more than 40,000 wells for farmers in 80 counties in Guangxi and neighboring provinces - nearly three wells a day on average.

"Looking for water is the only thing that I can do for the people with my knowledge," Chen says.

He thinks that water is the public wealth and nature's gift to all life on Earth.

"It is really a pity that a lot of water is polluted in China now. The change is irreversible," he says sadly.