Firefighters rushed to South Chesnut near American around 3 pm.
They say flames started on the outside of one modular home and then burned into the attic and some of the interior rooms.
Crews tried to use two different hydrants but discovered the entire privately-owned system was not working, so they had to rely on water tenders instead.
"It didn't change our operation but it did commit more resources than we needed to, and it's just a lot more convenient to use a fire hydrant than shuttle water back and forth in a water tender," says Fresno County Battalion Chief Ryan Michaels.
The Battalion Chief says if the fire had been fueled by strong winds or threatening other homes, the lack of working hydrants could have led to a lot more damage.
The cause of the fire is under investigation.