Our water supply in the United States has been tainted with lead almost since its inception and lead is a poison. Lead poisoning is serious. The toxicity of lead is not in question; the evidence is clear and overwhelming. Lead is toxic to living tissues including the kidneys, the heart and the nervous system and it affects the nervous system of children and can cause permanent neurological damage. Even small amounts of lead can cause behavioral or physical problems although there is some controversy on the exact minimum exposure that seriously affects the body. For this reason, lessening your exposure to lead in your tap water is a wise move. How can you do this effectively? Let us start by taking a look at the sources for lead in our water supply.
Water leaving the treatment plant should be free of lead. On its way to your home it passes through a variety of components that can leach lead into your water at the tap. Most lead in water leaches due to corrosion in copper tubing where the joints have been made using lead solder in your own home.
When I was learning the trade the most common type of solder was 50/50, fifty percent lead and fifty percent tin. Every coupling, every tee and every elbow was soldered with this poison. For soldering, this combination is easy to work with and makes solid joints. It heats faster and cools slower than the new “lead free” solders introduced in 1986 that require more skill to use. Although the health safety issues were clear, no plumber that I knew enjoyed using the “lead free” solders, mostly because there were more leaks from improper joints and more danger from using a torch inside a wall where fire spreading was a real concern. “Lead free” solder often did and still does have a small amount of lead; the allowable limit is 0.2 percent. Manufacturers note that even a tiny amount of lead helps the solder flow better. 50/50 solder is still available today for uses other than drinking water systems and is especially popular with electricians and in the electronics industry.
If you have copper tubing in your home that was installed before 1986 then it is likely the joints in that tubing were soldered with 50/50 solder. The lead in the solder will normally leach into the water due to corrosion especially when there is a low mineral content in the water or if the water is low pH (acidic). Since the copper tubing soldered with 50/50 would be over twenty years old and thinning due to corrosion it is wise to repipe your home simply to avoid potential flooding; older copper often develops pinholes. The lead content of the solder used is, therefore, not the only reason to replace your copper tubing. What if you do not know when the copper tubing was installed? If you are unsure as to the age of your copper tubing, you can have the joints tested for lead content and have sections of the tubing examined for their integrity.
The fluxes used to prepare a joint for soldering were generally fat-based and contained poisons that could slowly leach into the water supply. These fluxes were phased out for potable water systems along with lead solders in 1986, although they were still available for use on copper drainage pipe and could have been used in potable water systems illegally or by accident. The newer fluxes are water based and for that reason they flush out quickly, along with their contaminants.
Faucets are another hazard. Under the old government regulations faucets could contain up to a quarter pound of lead. California in 2006 and later Vermont and Maryland enacted statues to attempt to reduce the footprint of lead leaching from faucets to zero. In 2010 another law in California further reduced the allowable limit of lead leaching in fittings, fixtures and pipe. It is best to check with the manufacturer of the faucet or fixture you plan to install in your home to confirm that the lead content is zero or, at least, minimal. It is best to get this confirmation in writing, too. Faucets designed for the California market are required to be “lead free.” As usual, there may be a small amount of lead in the faucet but most government agencies consider that negligible.
What if you cannot afford to repipe your home and replace your faucets? Water filtration systems specifically designed to remove lead and similar metals are available to treat tainted water. These require periodic maintenance and become ineffective if that maintenance is not conducted regularly. Reverse Osmosis systems are effective as well but many are concerned that this water is unhealthy due to its lack of mineral content. It is important to note that filtered water passing through a leaded faucet increases the chance that lead will leach into your water. If you use filtration to remove lead take care to ensure that the water does not pass through and older faucet on its way to your lips.
In summary, water passes from the treatment plant through the city to your home. From there it usually passes through copper tubing and soldered joints to your faucets and fixtures. Most lead in tap water comes from soldered joints and from faucets laden with lead. The solution to reducing lead in your home water supply is to replace older tubing, replace older faucets with newer lead-free models, and filter out the remaining contaminants.