There are two very common, non harmful causes of cloudy water and one serious cause. In most cases, air bubbles or very fine particles of matter, such as dirt or organic matter get mixed in your drinking water. In very unusual cases, methane gas can cause this cloudy effect.
Air bubbles can form naturally in well water and can be created during pumping of municipal water. Cloudy water, also known as white water, can be created by air bubbles in the water.
It usually happens when it is very cold outside and air gets mixed in with the water supply. Sometimes it comes from the ground water source; other times it is a result of increased pressure of the water system or even by the pump in your well. It is completely harmless.
The best thing to do is let it sit in an open container until the bubbles naturally disappear.
Tiny particles from rocks and stone in earth, as well as sand and dirt can get suspended in your water supply. Again, these are generally harmless and more aesthetically displeasing. You may also see grit in the bottom of your sinks and tubs if particles are present.
You can usually differentiate particle from air bubbles by filling a clear glass and letting it sit for a few minutes. If the cloudiness is due to air, the bubbles will rise to the surface and disappear; if the water does not clear, it generally indicates particles are in the source of water.
Generally treating with a sediment filter will remove the particles. In some cases, unusual cloudiness can point to bacteria which would require disinfecting in addition to filtering.
The third and most unusual cause of cloudy water can be due to methane gas. Wells that contain methane are typically found in areas where gas and oil wells are common. Methane is objectionable in drinking water because of flammability.
It generally does not have an odor unless the water also contains hydrogen sulfide, which makes it difficult to detect. When suspended in water, the gas will perform with the same characteristics as air bubbles and rise to the top and dissipate.
Water containing methane gas should be aerated prior to use for household purposes. This is necessary to avoid the dangers of fire or explosion. The aerator must be vented to the open air to permit the gas to escape into the atmosphere.