Copper primarily enters drinking water when the water flows through plumbing materials containing copper or brass. It is not typically present in the source water itself or added by public water treatment facilities.
How Copper Enters Your Drinking Water
The presence of copper in your drinking water is almost always due to the interaction of water with the pipes and fixtures within a building's water distribution system. This process, known as leaching, occurs as water comes into contact with copper or brass components, dissolving small amounts of the metal into the water.
Common Sources of Copper in Plumbing
The main pathways through which copper can enter your tap water include:
- Service Lines: These are the pipes responsible for connecting your home to the municipal water main. Service lines can contain copper, and as water travels through or sits within them, it can pick up trace amounts of the metal.
- Household Plumbing and Fixtures: Inside your home, the internal plumbing system is a common source. Many homes utilize copper pipes for water distribution. Additionally, brass fixtures, such as faucets and valves, which are alloys containing copper, can also contribute to copper levels in the water.
Factors Influencing Copper Leaching
The amount of copper that leaches into the water can be influenced by several factors:
- Water Chemistry: Water that is more acidic (has a lower pH) or possesses certain mineral compositions can be more corrosive, leading to greater dissolution of copper from pipes.
- Stagnation Time: Water that has been sitting stagnant in pipes for extended periods, such as overnight or while residents are away, will have more time to dissolve copper, often resulting in higher concentrations when the tap is first turned on.
- Water Temperature: Hot water tends to be more corrosive and dissolves metals more readily than cold water, potentially leading to higher copper levels if hot water lines are primarily copper.
Understanding these pathways helps explain why copper might be present in your tap water, even if the public water supply is pristine. For more information on drinking water contaminants and safety, you can refer to resources from the U.S. Environmental Protection Agency (EPA).
