End cap of a pipe in the basement burst open

[vincent66502]

The end cap of a 3” pipe in my basement burst open today, releasing several gallons of water. The water appears to be clean and is not wastewater. It was raining outside but I am not sure if it was rain water. To investigate further, I turned on all my taps one by one, and no water came out of this pipe. I wonder what this pipe is for and how such a large amount of water ended up in it and even caused the end cap to burst open. Any assistance or guidance you can provide would be greatly appreciated. Thank you in advance for your help.