ᐅ How to deal with water damage in the basement caused by dripping?

Hello,

I accidentally discovered that the cold water supply line before the meter is now dripping—about one drop every 30 seconds, for roughly one day.

There is a slightly damp area measuring about 30cm x 30cm (12 inches x 12 inches). My concern is that water may have gotten between the floor and the wall, potentially causing mold to start forming or even damaging the masonry. I’m also worried that drying this out might only be possible with a dehumidifier, since the basement (in an older building) currently has a moisture level of 70%. I could open the windows all around to ventilate—would that help or make things worse?

Discovered just a day ago, or has it actually been dripping for only one day?
Depending on the size of the drip, we’re talking about a water volume of 0.2–0.4 liters (0.07–0.14 gallons), which is far from a water damage issue.
Use a hairdryer and open the windows wide, that’s it.
Of course, repeat the hairdrying several times, as the moisture is only removed from the surface. The wetness will come back up from underneath.

discovered today. But two days ago it wasn’t there, and that was the last time I was in the basement.
Yes, the amount of water is limited... I thought it would be more somehow...