Firebreaks aren't plowed in advance of a fire because you never know where will be. You also can't entirely rid a forest of all its deadfall and many live trees burn quite well. In this case, what was burning is the indigenous scrubby brush that dries out in drought but is actually still very much alive and its sap is very oily and combustible. As for water pressure, there is no way to mainain it when the entire town has their spigots trying to save a house that never had a chance.