A few months ago, we purchased a home that is 6 years old and found that the water coming from the kitchen sink is stagnant or moldy smelling when it is first turned on. The smell disappears after about 30 seconds. This week we noticed that the sink in the bathroom down the hall from the kitchen is doing the same thing. We have a bathroom in the basement and one on the third floor as well, but those sinks are fine. Any idea where I would start in finding the issue. The fact that it is in two sinks concerns me.

Thanks

It's one faucet for both hot and cold so the smell is there for the first 30 seconds regardless of whether it is set to hot or cold. The water supply comes from the city line. The water definitely smells when I fill a cup up with it, but again, only if its poured right away. After the water has ran for awhile, there is no smell at all.