The Baotu Spring is a culturally significant artesian karst spring located in the city of Jinan, Shandong, China. It is mentioned in the Spring and Autumn Annals, one of the Five Classics of Chinese literature, and was declared the "Number One Spring under the Heaven" by the Qianlong Emperor in the Qing dynasty.
The Baotu Spring is the most renowned among the more than 70 named artesian springs in the downtown area of the city of Jinan. The water of all these springs originates from an Ordovician karst aquifer under the city. As the terrain around Jinan slopes from the south down to the north, the recharge area for the aquifer is located in the mountainous area to the south of the city. The recharge area of the springs covers 1,500 square kilometres, out of which 550 km² provide direct recharge and 950 km² indirect recharge.
Altogether, the springs fed by the aquifer have a discharge of about 300,000-350,000 cubic metres per day. Since the 1970s, the springs have stopped flowing several times because too much water has been taken out from the aquifer for human consumption (more than 270,000 m3 per day in the 1970s).
The Baotu Spring is part of a cluster of about 20 named springs. Water age estimates suggest that its water originates from shallow circulation.
The spring pool of the Baotu Spring is fed by an underwater limestone water through three outlets, the volume of the water coming out of the spring can reach peak values up to 1.6 cubic metres per second. The water jets from the spring are said to have reached highs up to 26 metres. The water temperature remains constant of 18 degree Celsius through the entire year.