With all the new about the Lead levels in the Flint water supply, I thought it would be a good time to discuss lead and it introduction into our water supply and systems.
Numerous elements and minerals are present in our drinking water. Some occur naturally. Others enter or leach into the water on the journey from utility to faucet. Some of these elements are linked to emotional issues; most notably, lead.
History of Lead in Plumbing
Why is lead in pipes at all? The answer goes back literally thousands of years to the first plumbing systems, which are names for the word "lead" in Latin, plumbum. Lead piping was used because of its unique ability to resist pinhole leaks, while being soft enough to form into shapes that deliver water most efficiently. Lead was used in many other common products as well until scientific advancements in the 20th century demonstrated the element's toxicity. The plumbing industry voluntarily took significant steps to reduce lead exposure.
Lead is a common element found in the Earth's crust.
- The U.S. Environmental Protection Agency (EPA) reports that lead is the fifth most important metal in the U.S. economy in terms of consumption.
- Approximately 85 percent of the primary lead is produced domestically.
- Lead is mined and/or smelted in the following states: Missouri, Colorado, Idaho, Utah, Montana and Texas.
- Lead in Plumbing Today
Aging infrastructures, including pipe and plumbing system components, are the main contributors of trace amounts of lead in the water supply today:
Nearly all homes built prior to the 1980s still have lead solder connecting copper pipes.
Some major U.S. cities still have 100 percent lead piping bringing water from the utilities to homes and businesses. The dissolved oxygen in the water combines with the metal at the surface (copper, zinc or lead) to form a metal oxide. This oxidation layer naturally develops through the decades to coat lead piping. When water conditions require it, water utilities also add lime or orthophosphates as a further barrier to prevent lead from getting into drinking water. When water chemistry is carefully controlled, it prevents dangerous levels of lead from entering the drinking water system from the pipes.
Clean Water and Faucets
Many faucets sold in the U.S. and around the world are made from brass, a mix of copper, zinc and a minute amount of lead. Lead seals microscopic cracks that occur between the copper and zinc crystals as they cool, and provides the malleability for brass to be forged and converted into the machined components that are vital parts of every faucet.
In 2006, the American Waterworks Association Research Foundation (AWWARF) concluded that faucet lead levels in the U.S. leach less than 2 parts per billion, far below the allowable 11 parts per billion.
In recent years, a number of brass alloys have largely replaced the lead in faucets. These materials include bismuth, silicon, selenium, and phosphorous, all of which provide different material properties, depending on the amount used and method of processing.
While none yet effectively duplicates the performance of leaded brass, several types have been employed by some plumbing fitting manufacturers for certain applications.
Local Laws: California, Maryland and Vermont
Effective January 1, 2010, California, Maryland and Vermont's laws require the maximum allowable lead content in pipes, pipe or plumbing fittings, fixtures, solder, or flux intended to convey or dispense water for human consumption through drinking or cooking is as follows:
0.2 percent lead in solder and flux;
0.25 percent lead in wetted surfaces of pipes, pipe fittings, plumbing fittings and fixtures, as determined by a weighted average.
Pertinent plumbing fixtures include kitchen faucets, bathroom faucets and drinking water fountains.
PMI member companies have invested significantly in order to develop and manufacture products in compliance with lead-in-plumbing laws, to have those products certified, and to provide consumers with products that work and meet the needs of the consumer.
Eliminating Lead in Plumbing
The EPA has issued an online guide on certification markings for lead-free products. "How to Identify Lead-Free Certification Marks for Drinking Water System & Plumbing Materials" includes a summary of the law, its implementation, and a guide for identification of products that are certified as lead-free to the NSF 372 standard and California AB 1953.
It is essential to the nation's health that lead piping systems be upgraded, a task estimated by the EPA in 2003 to cost $276.8 billion and take more than 20 years achieve. In the meantime, the best protection for the U.S. public is the ongoing testing and monitoring of what makes up our drinking water. The amount of lead and other minerals that actually leach into the water is far more critical than how much is used to manufacture the products that come in contact with the drinking water.
The EPA allows faucets to be sold in the U.S. that do not leach more than 11 parts per billion of the lead into water during a 19-day test. That is comparable to a teaspoon of water in an Olympic-sized pool. The EPA's criteria is in accordance with the Safe Drinking Water Act (SDWA), taking into account the extremes of potable water chemistry that interact with the pipes and faucets across the U.S. Contrary to some erroneous claims, faucets do not increase the amount of minerals that are leached over time. In fact, the amount decreases over time.
Clean Water and Imported Plumbing Products
EPA officials addressing Plumbing Manufacturers International said that the EPA has reason to believe that faucets are being imported into the U.S. that contain lead in excess of the SDWA requirements of 11 parts per billion.
EPA is coordinating with U.S. Customs and Border Protection to identify imports that violate U.S. standards, working with environmental and law enforcement agencies to share information about noncompliant or suspect imports. Learn more on EPA's special import site by visiting here.