I live in a prewar co-op apartment in NYC and it takes 5-10 minutes for the cold water in my kitchen to get truly cold. It can start out anywhere between 70-80 degrees fahrenheit when first turned on and takes 5-10 minutes to drop to temperatures in the low 60s. The super and plumbers have looked in my apartment and they think the problem is in my apartment line somewhere. They tested my faucet but that wasn't the problem, they looked under the sinks of other apartments in my line and couldn't find any cross-connections between the hot and cold water lines, however other people in my apartment line experience the same problem and others in different apartment lines experience this problem and various other issues. The board president who lives in my building has a cold water temperature of about 68 degrees for 3 minutes which I think is high. I used to live in a different unit in the same building and never had an issue with the water, I tested it and the kitchen started at 58 degrees and the bathroom went from 69 to 58 in less than a minute. The board president think the water temperature in my current apartment of 70-80 degrees is normal and that there's not a problem. He said that water may start out cold when it's sourced from upstate but reaches "ambient" temperature when it sits in the pipes. I don't think this is true because my old studio in the same building didn't have this issue and neither do my parents who also live in an NYC apartment. I've talked to another plumber who say it sounds like an issue with the building. A friend of mine suggested a theory that one of the temperature controls that regulates my unit or line is not functioning properly or it could be an intermittent problem with the building. Others have suggested things like a leak in the water tank, a check valve on a water heater that needs to be installed, and circulation pumps. What do you think? NYC law states that all residents must have heat, hot, and cold water at all times. A lawyer I spoke to said there should be a constant, consistent supply of cold water from when the faucet is first turned on. However, he could only define cold water as water that is drinkable. How would you define COLD water that you would drink? Not tepid or cool but COLD. What temperature is ideal for drinking to stay hydrated? Any advice would be VERY MUCH appreciated.