Air in Your Water Supply

(My Original Blog Post: -*http://truthofwater.com/answers/2008/12/05/air-in-your-water-supply/)
Ais from Sydney, Australia writes:

I have been living in a building which was built in the 20's o r 30's. Our tap water is sometimes very milky/cloudy looking when it is first poured and then settles down to normal appearance when left to sit in a glass for awhile. My partner seems to think that it is just air bubbles, but I am concerned that it may be something else as we live in such an old building.

Any advice you may have would be greatly appreciated.

Hi Ais, thank you for your question.

Your partner is correct. This is indeed air.

There could be many reasons for a milky/cloudy appearance to water, but if it disappears without leaving any sediment than air is the reason.  This milky appearance is caused by extremely tiny air bubbles and lots of them.

Many people don't know this but air plays a very important part in the complex dynamics of a water distribution system. It is impossible to keep air out of water mains, and without the appropriate air vent/intake valves placed along that main, the main would constantly break or collapse.

It is possible that your building is located at a high point along the main where air can collect, introducing air into the apartmant buildings service lines on occasion.

But more likely the air in your water is due to occasional changes in water pressure due to increased demands else where in the distribution system.

Water naturally contains 2%-3% air by volume, being held in the water.  The higher the pressure you put in the water, the more air it can hold.  When the pressure is lowered, water can no longer dissolve as much air and the air is released from the water, forming air bubbles.  The same is true for temperature. Changes in temperature can effect how much air water can hold.

You may want to pay attention to when this is happening. Perhaps it's first thing in the morning, when most people are taking showers and getting ready for work. Or maybe it's later in the evening, when some industry ramps up it's use of water, filling storage tanks for the next day's processes. It could be seasonal, or the water pipes in the building could run parallel to heating/cooling duct work, changing the temperature.

Regardless, air in your water is normal and will not cause you any harm.

I hope I've helped answer your question. If you have any other questions or require further clarifications, please don't hesitate to write in again.