Does anyone know of a good reference that prescribes (in terms of temperature/climate) when to install dry barrel fire hydrants?  All the information I can find simply states dry barrel fire hydrants should be installed in colder climates, but I can't find any guidance as to how cold, i.e when to go with a dry versus a wet barrel.  The community in question is in Southern California, but at an elevation of around 4,500 ft, so they do typically get some snow and cold weather part of the year, but it's not severe or prolonged.  They don't currently have fire hydrants but will with the new proposed water system, so I don't have any testimonial to go on as to whether hydrants freezing are a problem.  I'll be making enquiries with other nearby communities on their experience, but thought I'd see if anyone here had a good reference/guide.  If I can avoid dry barrel hydrants I'd like to, to lower O&M and overall costs.