The United States is blessed with tap water that is safe to drink -- but that doesn't always mean it's pleasant to drink. Rotten eggs, mud, mold, and general mustiness are common complaints in locations around the country. Assuming your tap water comes from a source that is currently in good shape (no warnings about contamination or boil-water orders, for example), bad smells and tastes can be frustrating to deal with, especially if you just moved from an area with really good tap water. You can take some steps to remedy the problem, though, starting with stepping away from the sink.
Sometimes It's Not the Water
Take a look at what you're doing when you get water from the tap. Are you walking up and immediately turning on the tap, filling a glass, and drinking as you stand at the sink? The smell you encounter could very well be from the sink drain, rather than the water. Garbage disposals can trap food, and non-disposal drains can gradually build up a layer of smelly sludge on the inside. If you've just moved in and have pretty much been staying by the sink when you drink, move into another room that doesn't have a sink. Then see if the water in your glass still smells. If it doesn't, chances are whoever lived in your place before didn't maintain the sink drains. You can get a plumber in your area to clean those out for you.
Check the Temperature
Sometimes a grassy, moldy, or musty smell can show up unexpectedly in summer. This can be caused by harmless algal blooms that grow in reservoir water when temperatures turn hot. There's not much you can do to stop the blooms except wait until the weather cools down, so do what The Kitchn suggests, and either buy a water filter or keep a lot of citrus fruit, such as limes, ready for slicing into the water.
Stock Up on Fruit
Some tap water just tastes bad because of minerals in the water, and really all you can do there is to filter the water and add fruit or other flavorings to it. Plumbers can help you figure out what type of filter would be best for your needs if you want to go that way. Otherwise, lots of fruit, berries, and low-calorie drink flavoring powders may be your friends.
If the smell or taste is really bad and can't be covered up, and there are no algae issues or other citywide water problems, have a plumber check out your home's pipes. It's best to be sure there's no mold or muck sitting in part of a damaged pipe, for example.