Lead in Drinking Water

Prepared by:
Mary Beth St. Clair, Extension Toxicology Specialist

and

Sandra A. Zaslow, Extension Housing Specialist

Published by: North Carolina Cooperative Extension Service

Publication Number: HE-395

Last Electronic Revision: March 1996 (JWM)

What Are the Effects of Lead?

Exposure to low levels of lead over an extended period of time can have severe effects. Too much lead can damage your brain, kidneys, nervous system, and red blood cells. Those at the greatest risk, even with short-term exposure, are young children and pregnant women.

According to the U.S. Environmental Protection Agency (EPA), lead dosage that would have little effect on an adult can harm a small child. Lead in drinking water can be a problem for infants whose diet consists of liquids-such as baby formula made with water. Since they are growing, children absorb lead more rapidly than adults. That lead can then impair a child's development, resulting in learning disabilties or stunted growth.

How Does Lead Contaminate Drinking Water?

Most of the lead in drinking water in North Carolina comes from the lead in the plurnbing in the house, not from the local treatment plant or well.

Lead-contaminated drinking water is most common in recently constructed or very old homes. Many homes built in the early 1900's used lead pipes for interior plumbing. Lead piping was also used for many service cormections that join homes to public water supplies. In 1986, a nationwide ban restricted the use of lead pipes for drinking water supplies.

When copper pipes replaced lead pipes, lead solder and flux were often used to join the pipes. Lead solder is a major cause of lead contamination in drinking water today. The N.C. Building Code Council banned lead solder in 1985. Since 1988, solder that has a lead content over 0.2 percent must be labeled to say that it cannot be used for joints or fittings in any private or public drinking water system.

Homes with plastic drinking water lines, which are glued rather than soldered, should not have problems with lead contamination from pipes. However, household faucets may be a significant source of lead contamination. Chrome-plated faucets are generally made of brass, which contains 3 to 8 percent lead. Contamination can occur when water comes in contact with these fixtures.

The pH (acidity or alkalinity) of the water affects how easily lead dissolves from pipes, solder, or fixtures into the water. Corrosive water (which has a very high or very low pH) can dissolve lead from the supply pipes, faucets, or solder and flux used to connect copper pipes. Water can be tested to determine whether it is corrosive. Soft (water with a low mineral content), acidic water can dissolve lead from the pipes or solder of household water systems.

Water with a high mineral content may offer some protection from lead pipes or solder, as a mineral buildup on the inside of pipes prevents contact between water and the lead pipes or solder.

Does Your Home Drinking Water Contain Lead?

Have the water in your home tested. Some cities and counties conduct lead tests for free or a small charge. Private laboratories can test water; the fees range from $25 to $75. The North Carolina Cooperative Extension Service center in your county or the public health department can help identify certified private labs who do these tests. Mail-order labs can also be used to test for lead and other drinking water contaminants. Testing is the only way to tell if there are harmful levels of lead in your drinking water. You should consider testing if:

your home has lead pipes (pipes are dull grey, soft enough to be scratched with a knife or key).
your home has copper plumbing and / or chrome- plated fixtures.
you see signs of corrosion from your water (frequent leaks, rust-colored water, stained sinks, dishes or laundry).
you use water from a private well. Private water supplies can contain lead in the plumbing or the fixtures, or both.

If you live in a high-rise building, you may also want to test, because lead may not be as easily flushed out of the water system in these structures. You may also want to contact your water supplier to learn if the service cormection that joins your home to the public water supply contains lead.

How Do You Test?

A certified lab will analyze water samples using the EPA's sampling and analysis procedures. Be sure to have a "first drawn sample and a Ufully flushed" sample analyzed. The first draw sample should be collected after water has sat undisturbed for at least six hours. The first draw sample should have the highest level of lead. The fully flushed sample should be collected after the water has been running from the tap for several minutes, at least until the water becomes noticeably cooler.

This two-sample procedure indicates whether flushing the tap can reduce the lead to safe levels. You may be asked to take samples from all the drinking water taps in your home.

How Can You Treat Water To Remove Lead?

There are simple steps you can take if you suspect lead contamination or if testing shows that flushing the tap reduces lead levels.

Flush the water taps or faucets. Do not drink water that has been sitting in the plumbing lines for more than six hours. The longer that water sits in pipes, the greater the exposure to lead and possible contamination. Before using water for drinking or cooking, run the cold water faucet for two to three minutes, until you can feel that water has become as cold as it can get. You should do this for each drinking water faucet. Allowing the water to run an extra 15 seconds after it feels cold should flush the service connector as well.
Use only cold water for cooking and dnnking. Hot water dissolves lead more quickly than cold water. Using cold water is especially important if you are preparing baby formula. Heat the water you need for formula on the stove or in the microwave oven. (Do not mix the water with formula or baby food and then heat it in the microwave. Uneven heating could result in "hot spots" that could burn baby's mouth.)
Use bottled or distilled water. This water can be used for drinking and cooking if flushing the taps does not lower lead levels, or if your home has lead pipes.
Treat well water to make it less corrosive.
If you are building a home, state in writing that only lead-free materials are to be used for plumbing installation.
Use lead-free materials when repairing plumbing or remodeling.

Do Filters Reduce Lead Levels?

Calcite filters can be installed between the faucet and any lead service connectors or lead-soldered pipes. Point-of-use filters like reverse osmosis and distillation units can also be used. They must be maintained to be effective. Activated carbon filters, sand filters, and cartridge or microfilter filters do NOT reduce lead levels, according to the EPA. When lead is a problem, water softeners should not be connected to pipes leading to drinking water taps.

New Legislation for Lead

People can be exposed to lead from many sources, including air, soil, dust, food and water. Because of concerns about the health effects of lead, standards have been tightened to reduce total exposure to lead. The EPA has also reduced the amount of lead permitted in drinking water.

Since much of the lead which appears at the tap comes from household lines, rather than from the water supply itself, there is no longer a "Maximum Contaminant Level" (MCL) in place for lead. (An MCL is defined as the limit on the amount of a contaminant which may legally be present in municipally-supplied water). Instead, an "action level" of 15 parts per billion (15 ppb) has been established for lead in tap water. Other ways to express this level are 15 micrograrns per liter (ug / L), 0.015 parts per million (ppm) or 0.015 milligrams per liter (mg / L).

In addition, water systems have been informed that they should supply water which is free of lead. This is a non-enforceable goal, unless significant contamination is detected at the tap in homes supplied by the system.

Each municipal system must now target ahigh riskn households (based on materials used in the delivery system and other factors) and analyze tap water samples from these households for lead. If the lead level exceeds the 15 ppb action level in 10 percent or more of the taps sampled, then these three steps must be initiated by the supplier:

Corrosion control to adjust water pH so that it is less likely to damage pipes, solder, or fixtures, or any combination of the three. This will reduce the release of lead into the drinking water.
Source water treatment to reduce the amount of lead in the water as it leaves the municipal supply.
Public education to inform customers of the health effects of lead.
Finally, if the above steps do not reduce the lead level at the tap to the 15 ppb action level, then the municipal system must replace lead delivery system components which contribute more than 15 ppb to tap water lead levels.
Contact the North Carolina Cooperative Extension Service center in your county for additional in- formation and publications on water quality. Also, the EPA has a toll-free DrirMing Water Hotline to answer your questions about drirMing water testing and drinking water safety. Their number is 1-800-426-4791.

References
Lead and Your Drinking Water. April, 1987. Office of Water, United States Envirorlmental Protection Agency.
Lead in Drinking Water. Wagnet, Linda and Ann Lemley. 1987. Cornell Cooperative Extension. Cornell University.
Lead: Water Quality Fact Sheet 6. Plowman, Faye T. Cooperative Extension, University of New Hampshire.
"Lead in Water Can Be A Problem in New Homes." Mather, Tom. The News and Observer, Raleigh, NC. June 19, 1989, 1A, 4A.
Get the Lead Out! January, 1989. City of Raleigh Public Affairs Department.
"The Pollutants That Matter Most: Lead, Radon, Nitrate." Consumer Reports. January, 1990 30-32.
Lead and Copper Rule. US Environmental Protection Agency. Office of Water, WH550A. EPA 570/ 9-91- 400, June 1991.
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
HE-395

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