  In this Letter, we report Very Long Baseline Array observations of 22 GHz
water masers toward the protostar CARMA-6, located at the center of the Serpens
South young cluster. From the astrometric fits to maser spots, we derive a
distance of 440.7+/-3.5 pc for the protostar (1% error). This represents the
best direct distance determination obtained so far for an object this young and
deeply embedded in this highly obscured region. Taking into account depth
effects, we obtain a distance to the cluster of 440.7+/-4.6 pc. Stars visible
in the optical that have astrometric solutions in the Gaia Data Release 3 are,
on the other hand, all located in the periphery of the cluster. Their mean
distance of 437 (+51, -41) pc is consistent within 1-sigma with the value
derived from maser astrometry. As the maser source is just at the center of
Serpens South, we finally solve the ambiguity of the distance to this region
that has prevailed over the years.
