Answer:
The water was heated by magma or hot rocks.
Step-by-step explanation:
There are many places in the world where there are hot springs or geyzers. One thing that can be noticed about their distribution though is that they are very close to plate boundaries or close to hot spots. The reason for such a distribution is that volcanic activity is what causes their existence.
When there is groundwater near a volcano, there is a high chance that it will be hot and that in some cases it will be spectacularly propelled in the air. This happens because the magma directly heats up the water, or it heats up the rocks which heat up the water, so the water gains on temperature, lot of pressure builds up and comes out on the surface as hot water. Also, warm springs occur in palces where there aren't active volcanoes but there were some in the past, but because there is still higher temperature in the crust, they have higher temperatures.