Cox was also charged with possessing a shotgun, explosives and cultivation of cannabis.
Police alleged the men drove around Wellington, Rotorua, Hamilton, Tauranga and Auckland in a white Mitsubishi Delica Light Van. It's claimed they wore high-vis jackets while pretending to service the fire hydrants.
Instead, it's alleged, they removed the connections, which cost the taxpayer $1000 each to replace.
Police said the connections were sold to four different scrap metal dealers for $10 a kg.
"One guy [allegedly] took 120kg in so he made $1000 there, but it's endangering public safety," Detective Watson said. He said the illegal money-making operation had been running since February but the inlets weren't noticed missing until last month.
Insurance company Aon's technical services manager and engineer, Chris Mak, said the inlet, which looks like a hose nozzle, was used to connect the fire truck's hose to the hydrant and sprinkler systems.
He said a hydrant system would not work without the inlet valve but the sprinkler system would be able to operate, depending on the size of the fire.
Fire Service spokeswoman Karlum Lattimore said Wellington headquarters had also been hit by thieves but she would not identify other buildings as it was part of a police investigation.
A Waikato Hospital spokeswoman said "greedy metal thieves" had also struck at the hospital.
Waikato police inspector Karen Henrikson said firefighters discovered the first missing inlets during a callout to a fire at a central city shopping complex and the hospital was checked shortly afterwards.
"This has the potential to put not only the lives of firefighters at risk but those of medical staff and patients as well."
Takapuna police would like to hear from anyone who has seen the van, with registration BUB509.
