I have not yet encountered any definite Spanish privies in my work in 
Hispanic California, though there are plenty from Anglo and Asian-American ones 
in later phases of occupation at the Presidio of Santa Barbara. We did find a 
well of still yet undetermined date at the same site.   I suspect that the 
privies are more likely in military sites which are early and in the 
Southeast, at a point less remote from the center of civilization, such as St. 
Augustine or other sites in Florida.

The major question for me is what did the Spanish do about waste disposal 
at mission sites such as San Antonio de Padua where there were up to 1300 
Indians.   Chamber pots worked well for the 2 padres, five soldiers, and 
possible one or two others of European or mestizo origins, but were impractical 
for the large numbers of neophytes.   With the health ramifications of this 
issue, I cannot believe that this was just left to informal chance.   In the 
1790s, the Spanish were learning much more about the nature of disease and 
the role of public health.   However, so far we have found no traces of trench 
latrines anywhere.   I believe chemical analysis of the soil is the best 
bet for revealing this, as it leaves little visible trace behind.

Bob Hoover