Tap Water Quality and Treatment
World Health Organization sets international norms for drinking water quality requirements. There are many criteria to evaluate the quality of water, among them are taste and odor, color, dissolved metals and minerals, pH, dissolved organics, microorganisms, etc.
The drinking water supply can be divided into 3 major parts: source water, treatment system, and distribution system. The plumbing inside houses and apartments can be considered as an extension of the distribution system. The treating water for drinking purpose may include such processes as, solids separation, filtration, aeration, disinfection, removing heavy metals from water.
In 2005, in response to changes to the Canadian Drinking Water Quality Guidelines, Greater Vancouver Water District approved the combination of ozone and UV treatment to primary disinfect water. Compared to chlorine, ozone significantly reduces the by-products that may have health safety implications, provides faster and better disinfection, reducing the need for a big infrastructure. But chlorine is used as secondary treatment because the disinfectant used during the primary treatment stage gradually becomes ineffective in the distribution system.
Anyways, it is a good idea to run the water before drinking or using it for cooking, especially, if the tap system has not been used for long. Also it is better to use cold tap water for drinking or cooking since hot water may contain more dissolved impurity from distribution system. And make sure to deal only with reliable certified plumbers
As history evidences, water supply systems were invented and first used several thousands years ago. It was clay, copper and lead – the first materials that were used to make pipes. Initially, water supply was used in limited areas and the technology for cleaning water was not applied. Nowadays, running clean water delivered to our homes, businesses and public buildings. Modern pipes made of iron, steel, copper, or different types of plastics that are able to carry a sufficient water supply for all our needs. 
A special greetings to you from the Papa Plumbing family: We wish you a joyous holiday season and a new year filled with peace, happiness, and hope! Warmest Wishes for a Merry Christmas and a Happy New Year! May your plumbing and heating problems will be fixed in 2013 (if you still have ones)!
