Smell: Before you do anything, you should run the water for a few minutes (this will help with determining where the smell is coming from). If the smell is coming from all of your water faucets then there is an issue with your water supply. Most smells come from the presence of bacteria or metals (iron, copper, and lead) in your water.
If odor comes from one faucet and it goes away after a few minutes (or not) then you have plumbing-related issues. There is somewhere in your plumbing where the water flow is not smooth and organic material has allowed bacteria to grow, or the pipes are made from a material that releases material slowly and is trapped until it builds up to a level you can detect by scent. If the smell is detectable in the hot water side only, then you potentially have an issue with the magnesium rod in your hot water heater. For these issues you will need a plumber.
Looks: This is almost always due to sedimentation or scale (the material that collects on the insides of the pipes bringing water to your house). Sedimentation comes when water systems are flushed by the water provider (or well system) or when the water system is not used very often, allowing the sedimentation to build up. Opening your faucets and letting them flush out will usually take care of the problem. The release of scaling is due to a change in the chemistry (pH) of your water and will continue to look funny for a longer period of time. We can test your water for the amounts of sediment present and also its pH. If there is a change, you need to inform your water provider because contaminants can be released into your water.
Taste: is the most difficult to determine because of the natural amount of minerals in the water and the additives that your water provider may add to your water (such as chlorine). Taste is an individual preference—what bothers you may not bother others. Most tastes are actually a reaction to the odor of the water (the tests for which are mentioned above). Bacteria, algae, metals, and chlorine can all lead to different tastes in your water. There are many filtration systems available that will change the flavor of your water by removing the above (which may also remove potential contaminants).