Guide to Lead Contamination of Drinking Water 2023

Lead contamination poses serious health risks, especially to children and pregnant women.

This comprehensive guide aims to equip you with the knowledge and tools to effectively filter lead from your water supply, safeguarding your health and well-being.

Let's delve into the regulations and best practices for lead water filtration. Find out how to identify lead contamination, acceptable levels of lead in water, and what you can do about a lead water problem.

What is Lead?

Lead is a naturally occurring element found in the Earth's crust.

It is a heavy metal that has been used for centuries in various applications, from plumbing and construction to batteries and paint. 

It's notable properties are its high density and resistance to corrosion. In the past, these have made it a useful material in construction, particularly in water pipes and roofing.

However, now we are aware of its toxicity it is used much less extensively.

While it still has some beneficial uses (it's still commonly used in car batteries and for radiation protection), lead is toxic to humans and animals when ingested, inhaled, or absorbed through the skin.

Why is Lead Harmful?

Lead is a potent neurotoxin that can have severe and irreversible effects on human health. Here are some of the key reasons why lead is harmful:

Given the significant health risks associated with lead exposure, it is crucial to take steps to minimize or eliminate this toxic element from your environment, particularly from your drinking water.

In the following sections, we will explore how lead enters drinking water, the regulations in place to control it, and most importantly, how you can limit your exposure to it.

Sources of Lead Contamination in Drinking Water

Of course we can filter water to remove lead from it, but the ideal solution is to prevent it from reaching our water supply in the first place.

To do so we need to understand how it gets there. 

Lead in Plumbing

One of the most common sources of lead contamination in drinking water is outdated plumbing systems.

Homes built before 1986 are more likely to have lead pipes, fixtures, and solder. Over time, these components can corrode, releasing lead particles into the water supply.

A common source of lead in water is chrome or brass faucets (even chrome or brass plating) and plumbing that uses lead solder.

The Safe Drinking Water Act (SDWA) was updated in 2020 to limit the amount of lead used in household plumbing. 

The allowable amount of lead in plumbing fixtures labeled "lead free" was actually as much as 8% prior to 2014.

The changes meant that "lead-free" fixtures can now only contain 0.25% lead and this is "a weighted average of 0.25 percent of the wetted surfaces of pipes, fittings, and fixtures" (source).

So, the key takeaway here is that plumbing fixtures for drinking water that were installed before 2014 may contain as much as 8% lead.

However, to this day, even those labelled as "lead-free" may still contain lead! (U.S. Environmental Protection Agency).

Lead in Soil and Natural Deposits

Lead can naturally occur in soil and mineral deposits. In some regions, groundwater that comes into contact with these deposits can become contaminated with lead.

This isn't such a concern for those that receive municipal water but it's particularly concerning for those who rely on well water.

Industrial Sources of Lead

Factories, waste incinerators, and other industrial activities can release lead into the air, which can then settle into water sources.

Industries like battery manufacturing and metal smelting are significant contributors to lead pollution.

Municipal Water Supply Issues

Sometimes, the problem lies not in the home but in the municipal water supply. Aging infrastructure, including lead service lines that connect homes to the water main, can be a significant source of lead contamination.

Corrosion of Plumbing Materials

Water chemistry can also play a role in lead contamination. Factors like pH levels, temperature, and the presence of other minerals can cause corrosion of plumbing materials, leading to the leaching of lead into the water.

Imported Goods

Items like imported pottery, toys, and cosmetics can sometimes contain lead. If these items come into contact with drinking water, they can contribute to lead contamination.

Drinking Water Requirements for Lead

So, what else is the government doing to protect us from harmful lead contamination? 

EPA Lead Drinking Water Regulations

The EPA's drinking water regulations for lead are a little different to other common water contaminants.

Here's why.

The lead contamination of drinking water is frequently caused by corroding plumbing materials that belong to the water customers themselves.

With the source of contamination happening at the point of use like this, it becomes difficult to quantify. However, there are certain 'triggers' in the water composition that cause corrosion to happen easier and more quickly.

Therefore, the 'Lead and Copper Rule' which regulates the treatment of water for lead concerns the corrosivity of the water.

It also requires municipal water treatment plants to collect regular samples from sites that are more probable to contain lead in their plumbing fixtures.

They are required to take action if a threshold of more than 10% of samples exceed 15 parts per billion of lead (ppb). They must aim for a Maximum Contaminant Level Goal of zero ppm.

The next steps include:

Local water providers are required by law to publish annual water quality reports. If you're interested in the last readings for lead contaimnation where you live you can find it here.

In the United States, the Environmental Protection Agency (EPA) has set the action level for lead in drinking water at 15 parts per billion (ppb).

This means that if lead concentrations exceed this level in more than 10% of customer taps sampled, the water supplier must undertake additional treatments to control corrosion.

If the problem persists, the system must inform the public about steps they should take to protect their health and may have to replace lead service lines leading to homes (U.S. Environmental Protection Agency).

State and local regulations may vary, but they generally align with or are more stringent than federal guidelines.

For example, California has a Public Health Goal (PHG) for lead in drinking water set at 0.2 ppb, which is far lower than the EPA's action level (California Office of Environmental Health Hazard Assessment).

International Standards

Internationally, the World Health Organization (WHO) recommends a provisional guideline value of 10 ppb for lead in drinking water (WHO - pdf download).

This guideline is based on the modeling of lead intake from food and water sources and its subsequent health impact.

The European Union and the UK also follow a similar standard, setting the maximum allowable concentration of lead in drinking water at 10 ppb. The EU has stated that they will reduce this to 5 ppb by 2036. (EU Commision)

Canada has recently updated its guidelines, lowering the maximum acceptable concentration for lead in drinking water from 10 ppb to 5 ppb, effective as of March 2021 (Canadian Government).

Key Takeaways:

Acceptable levels of lead in drinking water as proposed by the EPA are 15 parts per billion (ppb).

However, this threshold can be lower depending on which state you live in. California for example, is just 0.2 ppb.

In the EU the limit is 10 ppb and Canada just 5 ppb.

Factors Affecting Corrosion of Lead Pipes

We learned in the last section that the main cause of lead contamination of municipal water (and sometimes well water too) is the corrosion of pipes.

This is a real problem.

Water treatment plants can remove every atom of lead at their end but the water may still become contaminated on its journey from the plant to leaving your faucet.

So, what exactly causes the corrosion and are some areas at more risk than others?

Water pH Levels: A lower pH level indicates acidic water, which can accelerate the corrosion of lead pipes. Conversely, alkaline water with a higher pH can form a protective scale inside the pipes, reducing corrosion (U.S. Environmental Protection Agency).

Water Hardness: Soft water is more corrosive than hard water. Hard water contains minerals like calcium and magnesium that can form a protective layer on the interior of pipes, reducing the leaching of lead (American Water Works Association).

Temperature: Higher water temperatures can accelerate the rate of corrosion. Cold water is generally less corrosive, but seasonal changes can still impact corrosion rates (Centers for Disease Control and Prevention).

Dissolved Oxygen: Higher levels of dissolved oxygen can increase the rate of corrosion in lead pipes. Oxygen reacts with lead to form lead oxide, which can then dissolve into the water (Control of Lead Corrosion).

Chlorine and Other Disinfectants: While chlorine is commonly used to disinfect water, it can also contribute to the corrosion of lead pipes. The interaction between chlorine and lead can result in the formation of soluble lead compounds (Scientific Journal by Edwards & Dudi).

Flow Rate: Stagnant water can lead to increased corrosion as it sits in contact with lead pipes for extended periods. Regular water flow can help reduce the concentration of lead (Agency for Toxic Substances and Disease Registry).

Pipe Age and Condition: Older pipes are generally more susceptible to corrosion, especially if they have not been well-maintained. The presence of cracks or damages can also accelerate the rate of lead leaching (U.S. Environmental Protection Agency).

How Can I Tell if There's Lead in My Water?

The only truly effective way of pinpointing lead in your water supply is to test water at the point of use (your faucet).

I'll explain how to do this reliably down below. I'll also cover the other (less reliable) possibilities at hand.

Municipal Water Reports

If you are connected to a municipal water supply, you can consult the annual Consumer Confidence Report (CCR) provided by your local water utility.

They are required by law to publish an annual report on the state of your water. You can find yours here.

This report includes information on lead levels in the community's drinking water. However, these tests are conducted at the water treatment plant.

Therefore, any contamination that occurs as the water travels from there to your mouth is not taken into account. As we've seen, lead contamination most commonly occurs in local water pipes and plumbing fixtures.

For this reason, the CCR reports alone are not sufficient for confirming lead contamination.

Visual Inspection

Lead itself is not actually visible in water. In fact, it's odorless and tasteless too. 

However, there are warning signs that we can look for.

Evidence of corroded plumbing like rust coloration or even low water pressure are both situations in which lead leaching can occur. Especially if you live in an older home or suspect that the water pipes in your neighborhood might be old.

However, a visual inspection alone is not sufficient for confirming the presence of lead.

Certified Laboratory Testing

The most reliable method for detecting lead in water is through laboratory testing.

This tests the water directly from your faucet.

This is an important distinction when it comes to lead pollution as the water has now left the pipes and plumbing fixtures which are a common source of contamination.

You can find a certified laboratory in your state using the pdf link on this page.

Your other option is to use an online service such as Tap Score.

Using one of their test kits you simply fill a sample and then send it off to the laboratory for it to be tested according to EPA methods.

You'll then receive an e-mail report that goes into various levels of detail depending on the test you chose.

The big upside with these kits is the quick turnaround time. You can expect to have your results within 5 business days. They're also very comprehensive tests that conform to industry standards and methods of analysis.

The big downside is the cost. The most thorough tests that analyze your water for multiple contaminants can get quite expensive.

Here are links to the lead specific test, city water test, and well water test. These all test for lead (among other contaminants):

Licensed Plumbers

If you suspect that your home's plumbing fixtures may contain lead components, a licensed plumber can perform an inspection.

They can identify lead pipes, solder, or fixtures and recommend appropriate action.

How Can I Reduce My Exposure to Lead?

There are various ways of reducing the likelihood of lead being present in your drinking water supply and I'm going to explain each of them in this section.

Inspect the Plumbing

If your home was built pre-1986 then it's very possible that you still have plumbing fixtures and pipes that contain as much as 8% lead (that was the old definition of "lead-free" pipes).

If you're at all worried about this then you need to hire a plumber who can survey your pipes and fixtures and create a plan of action (if needed).

These days, water pipes and fixtures safe for use at home are NSF-61 certified.

This guide is really useful for identification of lead free certification marks on plumbing fixtures.

Flush Your Pipes

This isn't a solution but it can reduce the concentration of lead in your water. Flushing merely means running the faucet for a minute or two before using it. This allows all of the water that may have been sitting in the pipes to escape.

It should be noted that you should never drink hot water from the faucet. Hot water dissolves lead from fixtures much more quickly than cold water.

Use a Water Filter

An effective water filter can remove almost all traces of lead from your water.

 However, it's crucial that you use the correct method of water filtration.

Here's what you need to know:

NSF/ANSI Standard 53 governs contaminant reduction claims of water filters. Therefore, if you want to be sure a water filter can be trusted to remove lead, specifically look for this badge and that lead is listed as one of the contaminants that is targeted. 

You can find a list of NSF certified water filters for lead reduction here.

In the case of reverse osmosis water filters you should look for NSF/ANSI 58.

It should be noted that NSF International is just one of the governing bodies that independently certifies water filters.

So, which types of water filter are certified for lead removal?

The most thorough method of home water filtration is reverse osmosis. It will remove practically everything from your water to a high degree.

This guide is really useful for identifying lead free certification marks on water filters and plumbing fixtures.

Distill Your Water

Distillation can remove lead from water to a high degree. 

The fundamental principle behind distillation is the conversion of water into steam and then condensing it back into liquid form, effectively separating it from contaminants, including lead. Lead, being a heavy metal, does not evaporate and remains in the boiling chamber.

You can buy a dedicated water distiller or even try and do it yourself.

Reduce the Corrosivity of Your Water

We learned earlier that lead present in the plumbing can more easily leach into water if the water is acidic (with low pH). 

Filters that neutralize acid and make your water less corrosive (usually by adding calcium and increasing the ph) prevent lead from leaching into your water.

However, they tend to make your water much harder which can cause its own problems with your plumbing.

Further Reading

Here are some great resources that cover lead contamination of water really thoroughly. The NRDC article is particularly interesting.

Penn State - Drinking Water Test Summaries by County

EPA - Basic Information About Lead in Water

CDC - Lead in Drinking Water

NRDC - Causes and Effects of Lead in Water

Journal - When Water Treatment Causes Lead Contamination