Lead in Drinking Water

Lead contamination poses a serious threat to the safety of drinking water in Pennsylvania. This colorless, odorless, and tasteless metal can go undetected in water. Exposure to lead in water places adults at higher risk for cancer, stroke, kidney disease, memory problems, and high blood pressure. At even greater risk are children, whose rapidly growing bodies absorb lead more quickly and efficiently. Lead can cause premature birth, reduced birth weight, seizures, hearing loss, behavioral problems, brain damage, learning disabilities, and a lower IQ level in children. The U.S. Environmental Protection Agency (EPA) states that lead is the most serious environmental health hazard for children under 6 years old in the United States. Blood tests for lead are often recommended for very young children to determine if lead exposure is occurring.

Where Does Lead Come From?

The chemical symbol for lead of "Pb" comes from the Latin plumbum, the root for "plumbing". Lead is an element so it does not break down into less harmful substances. Lead has been used as an ingredient in gasoline, paint, glassware, metal pipes, and food containers, all of which have contained varying amounts of lead. Therefore, even though lead has been banned from gasoline and most paint and is generally no longer used in food containers, some lead can be found in the food, paint, soil, dust, housewares, and drinking water of many American homes.

Lead exposure risks frequently co-exist in older homes. Lead paint and dust are typically present in the same homes that have multiple sources of lead in plumbing, that introduce lead in the drinking water. Leaded gasoline, largely replaced by unleaded mixtures since the 1970s, has caused lead contamination of soil near roadways and in urban areas.

How Does Lead Get Into Water?

The most common source of lead in water is lead service lines and household plumbing. For this reason, lead is a potential concern for all homes whether on a public (municipal) or private (individual well or spring) water supply. Depending on its other chemical characteristics, the water itself dissolves lead from leaded solder or lead pipes in plumbing systems in a process called "corrosion". In rare instances, lead gets into water as a result of pesticides that were used decades ago or industrial activity that contaminate soil and groundwater.

Lead can also corrode from metal faucets and fixtures made from brass, an alloy of copper and zinc that often contains lead, including chrome-plated brass fixtures. Brass fixtures can leach lead even in homes with plastic water lines. Solder is an alloy of tin with lead, antimony, or silver. Lead may also originate from the corrosion of brass fittings on certain types of submersible pumps used in groundwater wells through the mid-1990s. The allowable lead content of household plumbing has been decreasing over time. Prior to 1986, there were no limits on lead in plumbing. The first time "lead-free" plumbing was defined, it could contain up to 8% lead by weight. Since 2014 the definition of "lead free" plumbing means that the device contains up to 0.25% lead by weight. Galvanized steel pipe contains lead and can absorb lead from other lead sources that can be released again into the water. Older homes can have any or all of these lead sources in their plumbing. Corrosive water also degrades copper plumbing, which may produce small leaks, blue-green stains, or metallic tastes, but these are not reliable indicators of the risk of lead in water. You cannot see, smell, or taste lead in water.

The amount of lead corroded from metal plumbing generally increases as water corrosivity increases. Water corrosivity is controlled primarily by the water's acidity and calcium carbonate content. In general, acidic water that has a pH less than 7 and that is low in calcium carbonate is more corrosive than water that has a pH higher than 7 and that is high in calcium carbonate.

In addition to acidity and calcium carbonate, many other factors can influence water's corrosivity. Soft water (low in dissolved solids like calcium and magnesium) tends to be more corrosive than hard water (with high concentrations of calcium and magnesium), and warm water is more corrosive than cold water. The common practice of grounding electrical connections to water pipes also can increase lead corrosion. Despite these general rules, any kind of water--including hard, soft, acidic, or non-acidic--can contain dangerous amounts of lead.

Corrosive water is a common natural problem in Pennsylvania. For example, of the over 6,000 water samples (mostly from private water wells) that were tested by the Penn State Agricultural Analytical Services Laboratory, about 67% were found to be potentially corrosive. Groundwater and surface waters in Pennsylvania often originate from sandstone and shale rock types that naturally produce relatively acidic and soft water. Common exceptions are water supplies in limestone valleys. Here interaction with limestone produces less acidic water that is higher in calcium carbonate hardness and is relatively noncorrosive. Water from cisterns and some springs resembles rainwater, which is naturally corrosive. For more information on corrosive water, see the Penn State Extension fact sheet.

Corrosive water acts to dissolve lead from pipes and solder while the water is in contact with the plumbing. Therefore, lead concentrations in drinking water usually are the highest in the first water out of the tap; sometimes they decrease as the water is run. If lead pipes, leaded solder, or brass fixtures are present, even relatively noncorrosive water can dissolve dangerous amounts of lead when the water sits in contact with these materials.

Conversely, if your town's water distribution system and your home plumbing system do not contain lead pipes or lead solder, and you have fixtures installed after 2014 you have a lower risk of lead exposure.

How Much Lead in Water is Too Much?

Guidance from the Centers for Disease Control suggests that blood lead concentrations over 3.5 micrograms per deciliter of blood (µg/dL) may indicate lead poisoning. Various studies have found that blood lead concentrations are positively and significantly related to the amount of lead in drinking water.

The U.S. EPA has set an action level for lead at 15 µg/L that is an indicator of corrosion control effectiveness. There is no safe level of lead exposure. EPA has set the Maximum Contaminant Level Goal (the level at which there are no negative health effects) at 0 µg/L for lead.

How Common is Lead in Drinking Water?

In Pennsylvania, the prevalence of leaded plumbing components and corrosive sources of water suggests that lead contamination is a common problem.

A survey of private water supplies (individual homes using groundwater wells) across Pennsylvania in 2006 and 2007 found that 12 percent contained concerning lead levels of above 15 µg/L. The survey also found that high lead levels could nearly always be explained by corrosion of lead from metal plumbing components.

Samples submitted to the Penn State Agricultural Analytical Services Laboratory are not a random sample of water supplies, but they do indicate that lead in drinking water is a problem in the state. Of the 4,500 first-draw lead tests from 2007 through 2024, about 10% exceeded the 15 µg/L lead action level

The prevalence of lead in public water supplies at the tap depends on how corrosive the source water is, whether lead distribution lines are used, and whether a particular building contains leaded plumbing materials. If your home is connected to a public water supply, you should contact your water company to find out if you have a lead service line. You should also review the plumbing materials or dates of plumbing installation in your home to estimate the risk of higher lead-containing materials in your plumbing.  You also may want to have your tap water tested, especially if you live in an older home (metal plumbing installed prior to the early 1990s), have young children, or have signs of corrosive water discussed above.

How Should You Test Your Water for Lead?

Because lead is colorless, odorless, and tasteless in water, the only way to estimate your risk of exposure is to identify the range of lead-containing materials in your plumbing system and conducting a water test.

Lead sampling can show a wide range of results, especially when particulate lead loosens from plumbing. Particulate lead is a form of lead like tiny grains of sand that loosen from the pipes or plumbing and are released into the water. Disturbances, like replacing a water meter, or nearby construction and excavation activities, increase the risk of particulate lead release because the work can shake particulates free from pipes and plumbing. Particulate lead is a concern because the lead content can be very high. A lead particulate could end up in a single glass of water, but not in water sampled just before or after.

When testing for lead in your drinking water two types of samples can be collected- a "first-draw" or "first-flush" sample and a "running" sample. The first-draw sample determines if lead accumulates in your water as it sits in contact with the plumbing system. Therefore, it is best collected first thing in the morning from cold water that has sat in the plumbing system overnight. Running sample is collected after allowing the cold water to run for at least one minute. Comparing the results helps you determine the source of a lead problem. A lead concentration that remains above 15 µg/L after the water has run for one to two minutes indicates that lead is probably present in the water before it enters the household plumbing. The lead may originate from water supply contamination, from corroding submersible pump parts, or from corroding lines in a public water system

A list of state-accredited water testing labs is available in PA Department of Environmental Protection Accredited Laboratories (PDF). Instructions on how to search through the laboratory database are available online. Make sure to ask and pick up bottles and instructions for testing lead in drinking water. Costs for testing lead in water normally range from $15 to $100. It is best to have your water tested for "total lead," which includes particles, rather than just "dissolved lead," which will ignore particulate lead in the water.

Laboratories sometimes use different units in their report. The most common units are µg/L (micrograms per liter, equal to parts per billion, or ppb) and mg/L (milligrams per liter, equal to parts per million, or ppm).

If your test result is reported in µg/L or ppb, then you should compare it with the safe drinking water standard of 15 µg/L. If your result is reported in mg/L or ppm, then the comparable drinking water standard is 0.015 mg/L.

What Regulations Control Lead in Drinking Water?

Public water suppliers are required under the federal Safe Drinking Water Act and its amendments (and related EPA and PA DEP regulations) to test their water for many contaminants including lead, and in some cases, to provide corrosion control to prevent lead from entering drinking water. These results are sent to customers in an annual report.

The federal Lead and Copper Rule (1991, revised in 2000, 2007, and 2021) requires that public water suppliers monitor tap water lead concentrations in high-risk homes they serve (e.g., older homes). If more than 10 percent of these homes exceed 15 µg/L of lead, the water supplier must provide public education on the lead problem, and the water must be treated at a treatment plant to make it less corrosive. In addition, the lead service lines owned by many water companies may have been replaced or may need to be replaced.

While these regulations help reduce drinking water lead concentrations in homes using public water supplies, they will not eliminate the problem. The variability of household plumbing systems within communities may mean individual homes still contain dangerous drinking water lead concentrations, even while most of the community does not have a problem. Also, the regulations provide little protection for homeowners with private water systems such as drilled wells, springs, and cisterns.

In 1986, Section 1417 of the federal Safe Drinking Water Act was amended to limit the content of lead in pipes and other materials used in water supplies, defining "lead-free" as less than 8% lead in pipes or fixtures and less than 0.2% in solder. The 1989 Pennsylvania Plumbing System Lead Ban and Notification Act (effective in 1991) and the 1996 SDWA amendments extended lead regulations further, including private water supplies by requiring "lead-free" pipe, fittings, and fixtures in new construction and replacement parts.

Since 1991, new homes to be served by public water suppliers must be certified lead-free before connecting to the system. Some mortgage programs may also check for lead-free plumbing. If your home plumbing system is made of copper pipe and was installed before January 1991, it is likely that lead solder was used.

The 2011 federal Reduction of Lead in Drinking Water Act redefined "lead-free" to up to 0.25% lead on surfaces in contact with drinking water for consumption, with solder still less than 0.2% lead. The PA Lead Ban Act was amended in 2014 to the same lead levels.

Some independent organizations test and certify products for lead content. For a current list of organizations and pictures of their certification marks see the U.S. EPA publication on How to Identify Lead Free Certification Marks for Drinking Water System & Plumbing Products (PDF). The European Union term "RoHS-certified" appears on some product labels which have less than 0.1% lead. In 2020, the committee that governs plumbing safety standards in the United States and Canada revised the NSF 61 certification test to allow 5 times less lead to leach into water from faucets certified under this test. This new requirement came into full effect on January 1, 2024, and it is mandatory for all faucets and other plumbing components, including connector hoses and shut-off valves. 

What Can You Do to Reduce Lead in Your Drinking Water?

If your first-draw water test result contains detectable lead or if you identified multiple sources of lead in your plumbing, you should take corrective action. Lead can be removed from water through numerous treatment methods depending on the cost and effort you are willing to expend.

The most reliable way to prevent exposure to lead in water, especially in places with older plumbing, is to use a filter that is certified to reduce lead in drinking water for all drinking and cooking water.  NSF/ANSI 53, NSF/ANSI 58, and NSF/ANSI 42 are the drinking water treatment certification standards you are likely to see. If you are selecting a device to remove lead, the package needs to state that it meets NSF/ANSI 53 or 58 for the reduction of lead. It is very important to follow the manufacturer’s instructions for changing the filter cartridge. 

The most permanent lead prevention method is to replace the leaded components in the plumbing system with newer, non-leaded components. This procedure most often involves replacing copper pipes and lead solder with plastic PVC or PEX pipes. Only plastic PVC or PEX pipes approved for home plumbing use, as indicated by "NSF-61" or "NSF-PW appearing on the side of the pipe, should be used for replacement. However, even “lead-free” plumbing contains lead.

Replacing home plumbing components will be effective if the only source of the lead is within the home plumbing system. If the lead originates from lead service lines within a public water system, this method should be coupled with lead service line replacement and/or point of use filters.

Before drinking or cooking, flush your home pipes by running the tap, dishwasher, or doing laundry. This may help lower lead levels by getting rid of the water that has been in contact with the plumbing for several hours. However, flushing alone is not a reliable form of lead control. 

Homeowners who have a groundwater well with a submersible pump may want to have the pump checked. If some of the pump's metal parts are corroding, they could be contaminating the groundwater with lead.

Acid-neutralizing filters can be installed to reduce water corrosivity by adding calcium and by increasing the pH of the water. Unlike other treatment options, these filters act to prevent lead from entering the water rather than removing it at the tap. In addition to reducing acidity, the added hardness produces a thin scale inside the pipes that reduces lead corrosion. These units normally cost over $1000 and may cause a noticeable increase in the hardness of your water.

Contrary to some claims, water softeners are not recommended for lead removal. Softeners are inefficient lead removal devices, and they usually are installed in the plumbing system ahead of the piping and fixtures where most of the lead originates. Also, softened water is usually more corrosive than un-softened water.

Reverse osmosis units and activated alumina filters are very effective in removing lead once it is in the water. These units typically are attached to the kitchen tap and treat only the water from that tap. Costs vary from $300 to more than $1,000. Reverse osmosis units of this size can produce only a few gallons of treated water per day.

Distillation units, also normally placed on the kitchen counter, are effective in removing lead from drinking water. However, they are relatively expensive to operate and produce only a gallon or so of water per day, depending on their size.

Lead in drinking water presents a complex problem for consumers of public and private water supplies. If you have questions concerning testing and removal of lead from your drinking water, contact your local office of the Pennsylvania Department of Environmental Protection, your county office of Penn State Extension, or the county or state health department.

For More Information

Lead in drinking water presents a complex problem for consumers of public and private water supplies. If you have questions concerning testing and removal of lead from your drinking water, contact your local office of the Pennsylvania Department of Environmental Protection, your county office of Penn State Extension, or the county or state health department.

To learn more about lead in drinking water, consult the following references.

• U.S. Environmental Protection Agency - basic information on lead in drinking water.
• Centers for Disease Control, About Lead in Drinking Water.
• Swistock, B.R., S. Clemens and W. Sharpe. Drinking Water Quality in Rural Pennsylvania and the Effect of Management Practices. Center for Rural Pennsylvania, Final Project Report, January 2009.
• Drinking Water Test Summaries, Penn State Agricultural Analytical Services Laboratory, 2024.

Based on Lead in Drinking Water, 1994, by Bryan Swistock and William Sharpe. Updated January 2016 by Amy Galford and Bryan Swistock. Updated in 2024 by Elin Betanzo, Yanna Lambrinidou, and Faith Kibuye.