The connections are next to or outside buildings and allow firefighters to boost the pressure in fire sprinkler systems or provide water to fire hoses inside a structure.
The thefts pose a risk to the public and businesses if there is a fire.
"The fire is going to get bigger, and it will take longer to suppress it," fire department spokesman Jeff Granberry said Tuesday.
The thefts were first reported by businesses to the Redding Fire Department about a week ago. Granberry did not know the specific number of connections that have been stolen or the buildings where the thefts have taken place.
Thieves typically get $15 to $25 for each brass connection at a salvage yard. Granberry estimated the connections cost $500 to install.
Granberry suspects the thefts are another sign of how desperate people are in these tough economic times.
"I would equate it to the copper wire thefts that have happened at construction sites," he said. "It's just another way for people to get money. Little do they know that this is really putting lives in jeopardy by removing a crucial piece of equipment."
Firefighters have not yet been called to a building where a connection has been stolen, but Granberry worries it will be just a matter of time before that happens.
The Redding Fire Department asks businesses to report suspicious activity by calling 911. Businesses should check their connections regularly and report a theft immediately.
Salvage yards should never accept any brass painted red that states: "Fire Department Connection" or that has threaded hose couplings, Granberry said.
The fire department has not received any reports from area salvage yards.
"In doing some research, we found out that this has been a big issue in