Did you do a water change with the brown water?
When there is a main break, sometimes biofilm breaks off when the water is turned back on, this is brown but highly unlikely to kill your fish.
Before the water supplier is allowed to put the main back in service, tests must be done to determine if it's safe for "human" consumption. They must double dose the fixed area with chlorine to make sure their customers are safe from E coli or other contaminants.
The people who do this work are not bureaucrats, they are working people with the responsibility to keep an entire population of your city safe from disease, this sometimes puts them at odds with fish keepers.
If you did a water change with brown water, and didn't treat it for chlorine, this is not the city workers fault.
When there is a main break, sometimes biofilm breaks off when the water is turned back on, this is brown but highly unlikely to kill your fish.
Before the water supplier is allowed to put the main back in service, tests must be done to determine if it's safe for "human" consumption. They must double dose the fixed area with chlorine to make sure their customers are safe from E coli or other contaminants.
The people who do this work are not bureaucrats, they are working people with the responsibility to keep an entire population of your city safe from disease, this sometimes puts them at odds with fish keepers.
If you did a water change with brown water, and didn't treat it for chlorine, this is not the city workers fault.