No, this is not some exotic spa that we went to over the holidays. A pozo negro is a septic tank and for the past week, ours has been full. We have lived here for almost a year and a half and never had the septic tank emptied. It is quite a large system, but even large systems eventually get full. The average house, here, on the Costo de Oro, has one or more large septic rings, which will cascade into one another, until they are full. Since the ground is mostly sand, it just leaches into the ground easily (a good reason not to ever drink water from a well, here). When another ring is needed, they will just dig it out by hand, install the ring and the capacity of the system just became doubled. It is not uncommon to pump out the septic system every 3-4 months, depending on the size.
One advantage we had was that there were two separate covers. The picture shows the two holes- one on the left is the pozo negro and the one on the right is a camara (or chamber where all of the pipes come together). The pozo negro, itself is an engineered system and should last for at least a year, before having to be pumped out. However, it had probably lain dormant so long, and we not realized that it would need to be taken care of. So it was good news when the truck came this morning.
They successfully emptied it and the total cost was 1100 pesos (about $55 US). They charge by volume. At least now we can face the new year without fear of overflowing the covers . I am going to go out and clean off the patio, now and then take a shower- secure in the knowledge that the shower water has someplace to go.
I think this gives new meaning to the phrase- "Out with the old and in with the new".