Visitors to the Alamo often ask about the well located behind the long barracks. This well is not original and is of modern construction. Despite reports to the contrary, it is doubtful that a well ever existed here for on the various maps drawn by Navarro, Jameson and Potter, this well is conspicuously missing. Later photos of the site clearly show that there was no well. Most likely, this was a "proposed" well for the Convento, much the way the San Antonio de Valero chapel was the "proposed" church for the Mission. When the chapel collapsed and mission was abandoned in 1794, any plans for a well were abandoned too.

With the presence of a nearby acequia and the close proximity of the Rio de San Antonio, such a well would have only been necessary in time of siege. According to Navarro's map, the well that was present during the battle was in the larger compound area and much further to the West. The Convento area was examined by archaeologists in 1967, but little of significance was found. In 1995, archaeologists made an unsuccessful attempt to find the well described on the Green Jameson map. This was located immediately in front of the chapel at the southwest corner of the long barracks. This excavation yielded little more than some interesting geological data and a few mission-period artifacts. So Jameson's well was either incorrectly drawn or was, like the Convent well, only a proposal.