I’m sitting in my unfinished basement and I’m looking up at the waterline. I noticed the water lines are like sweating with condensation on the outside. Perhaps this happens a lot and I just never noticed? What do you think? The water is working fine and there’s no leaks in the basement.

They can certainly sweat, particularly if the house is warm, the cold water pipes will sweat. A simple test to see if you have a leak is to shut off all water in the house and go look at the meter if ya can, if it's still turning numbers you have a leak.

 

That said it's the warmest day of the year so far but the ground is still cool, so your cold water from the main is as well. So if you're not running ac yet that could cause them to sweat.

Cold water in lines plus warm basement equals condensation.

 

Here you go, easy fix...

It’s very humid today so my guess is condensation.