Folks that can do this are pretty common in these parts and most of them are for real. I've witnessed it in person myself - I even have a friend who is very shy about the "talent" but is dead accurate when he is talked into doing it.
I asked him to check my place out up here on the ridge many years ago and he about went nuts on me, because his rods indicated water practically
everywhere in about a 100' wide x several hundred foot long area of the field.
Of course, I didn't tell him about the underground "lake" that's below part of our property, the one the spelunkers from UT had discovered years before.
They described it as "huge" with an enormous colony of bats. Helped me to decide to run a quarter mile of waterline up the ridge from the city main below instead.