If you are in Oaxaca and it’s the fourth Friday of Lent, it must be Día de la Samaritana (AKA, el Día de las Aguas) — a uniquely Oaxacan celebration. It is inspired by the Gospel of John story in the New Testament: At noon, a tired and, apparently, thirsty Jesus, on his way to Galilee, asks a Samaritan woman at Jacob’s Well in Sychar for some water. His request was highly unusual because, according to the Old Testament, “Jews regarded the Samaritans as foreigners and their attitude was often hostile.” The woman complied with his request and the rest is history.
By noon, this past Friday in Oaxaca, the thermometer had already reached 90º F in El Centro Histórico and people of all ages, from small children to abuelos, were already lined up at bougainvilla and palm decorated booths in front of churches, schools, and businesses for the traditional Día de la Samaritana free aguas. It wasn’t just plain water they were waiting on, it was for divinely flavored aguas frescas made with fresh fruits and flowers — jamaica, horchata, chilacayota, tamarindo, sandia, and others. However in front of the churches, prior to the offering of aguas, there was a reenactment of Jesus and the Samaritana, as well as a priestly blessing — and an article in Noticias reported that, given the blazing hot sun, some in the crowd became a little impatient.
All were eventually served and the streets were filled with smiling people drinking a rainbow of aguas. Within an hour the serving pots, pitchers, bowls, and buckets were empty and all that remained were garbage containers filled to overflowing with plastic cups.
By the way, talking to my friend Sam, who teaches at Universidad José Vasconcelos de Oaxaca, they had an aguas frescas contest — memorable combinations of watermelon with strawberries and lime; atole with tuna nieve; and coconut with strawberries. However, I was informed the day’s winner was the piña colada — alas, minus the rum, I’m thinking.
Mexican Peso Converter
View From Casita Colibrí 
Interesting, and great photos! Did they have this at the Alcalá after all, or at the various churches?
A large-ish tented station on the Alcalá in front of Sangre de Cristo and then card table size stands in front of some shops and the university, as well as scattered throughout side streets.
Sounds logical to me. A long-ago botany professor told us that alcoholic beverages were discovered as soon as people made bowls. Someone left liquid in a bowl for a week or so, stuck his finger in and tasted; “mmm, that’s good!”
… and the rest is history! It’s got to be the way tepache was first made/discovered.