Copper is an essential mineral that the human body needs in small amounts. However, too much copper in drinking water can cause health problems, particularly at elevated concentrations. Copper contamination is also relatively unusual because it often doesn’t originate at the water treatment plant—it can enter drinking water as water travels through household plumbing.

If you’ve noticed a metallic or bitter taste, blue-green staining around faucets, or unusually high copper levels in a water test, your plumbing may be contributing copper to your drinking water.

This guide explains what copper is, where it comes from, the EPA’s drinking-water requirements, how to test for copper, the best filtration methods, and what to look for when choosing a copper-reduction water filter.

This article is part of the RevOsmo Drinking Water Contaminants Explained series. For an overview of copper, lead, PFAS, arsenic, fluoride, nitrates, chromium-6, mercury, and other drinking-water contaminants, visit the Drinking Water Contaminants Explained pillar page.

What Is Copper?

Copper is a naturally occurring metal and an essential nutrient. Small amounts are required for normal biological functions, including the formation of red blood cells and maintenance of connective tissue.

The problem occurs when people are exposed to excessive amounts.

Unlike some contaminants that primarily enter water at the source, copper in household drinking water commonly comes from plumbing materials. Corrosion of copper pipes, faucets, fixtures, and other plumbing components can release copper into water. EPA identifies plumbing materials as the primary source of copper in drinking water.

Copper levels can be higher when water has been sitting in household pipes for several hours, particularly in homes with copper plumbing.

Where Does Copper in Drinking Water Come From?

Potential sources include:

Copper plumbing pipes
Faucets and fixtures
Corrosion of household plumbing
Water with acidic or corrosive characteristics
Industrial contamination
Mining activities
Natural deposits
Plumbing systems with long water-contact times

The source is important because treatment at the municipal water plant may not eliminate copper that is subsequently introduced by a home’s plumbing.

Is Copper in Drinking Water Dangerous?

Copper is necessary for good health, but excessive exposure can cause adverse effects.

EPA identifies stomach and intestinal distress, liver and kidney damage, and anemia as potential health effects associated with high copper exposure.

Short-Term Exposure

High concentrations of copper can cause gastrointestinal symptoms such as:

Nausea
Vomiting
Stomach cramps
Diarrhea
Abdominal discomfort

The risk depends on the concentration and amount consumed.

Long-Term Exposure

Long-term exposure to excessive copper can affect the:

Liver
Kidneys
Blood
Digestive system

People with Wilson’s disease may be particularly susceptible to copper-related health effects. EPA specifically identifies people with Wilson’s disease as potentially being at greater risk than the general population.

Can Copper Cause Cancer?

The EPA’s current technical information states that there is inadequate evidence to determine whether copper has the potential to cause cancer from lifetime exposure through drinking water.

Therefore, copper should not be characterized as a proven drinking-water carcinogen.

EPA Guidelines for Copper in Drinking Water

Copper is regulated differently from many contaminants with a conventional maximum contaminant level.

The EPA uses an Action Level for copper under the Lead and Copper Rule.

EPA Copper Action Level: 1.3 mg/L

The federal copper Action Level is:

1.3 mg/L (1,300 ppb)

The Action Level applies when copper concentrations exceed 1.3 mg/L in 10% or more of the tap-water samples collected under the regulatory monitoring program.

This is an important distinction.

Action Level vs. MCL

Copper’s federal regulation does not work exactly like contaminants with a traditional MCL.

The EPA’s copper:

Maximum Contaminant Level Goal (MCLG): 1.3 mg/L
Action Level: 1.3 mg/L in 10% or more of applicable tap-water samples

The EPA’s copper regulation is designed around controlling corrosion and reducing exposure from drinking-water plumbing.

What Does 1.3 mg/L Mean?

A concentration of 1.3 mg/L is equivalent to approximately 1.3 parts per million (ppm), or 1,300 parts per billion (ppb).

That may sound like a small amount, but it is substantially higher than concentrations of many other regulated contaminants.

Importantly, your individual household water sample can contain elevated copper even if your municipal water system is meeting its regulatory requirements.

This is because copper can enter water after it leaves the treatment plant, as water contacts plumbing.

How to Test for Copper in Drinking Water

The only reliable way to determine whether your drinking water contains elevated copper is to test the water.

You cannot determine the concentration accurately by taste or appearance alone.

1. Check Your Local Water Quality Report

If you receive municipal water, start with your utility’s annual Consumer Confidence Report.

The report can provide information about water quality and regulated contaminants monitored by your water provider.

However, because copper can enter water from household plumbing, a utility report doesn’t necessarily tell you exactly how much copper is coming from your own pipes.

2. Test Your Tap Water

A laboratory water test can determine the copper concentration at your specific faucet.

For homeowners concerned about plumbing corrosion, testing the water directly from the tap can be especially useful.

3. Consider Testing Different Samples

If you suspect household plumbing is contributing copper, consider discussing different sampling approaches with your laboratory or water professional.

For example, comparing water that has been sitting in the plumbing with water collected after flushing the line can provide useful information about whether household plumbing may be contributing copper.

4. Use an Accredited Laboratory

Professional laboratories can analyze water samples for copper using sensitive analytical techniques.

EPA-approved methods for metals in water include Methods 200.7, 200.8, and 200.9, depending on the analytical requirements.

For homeowners, the practical approach is simply to use a qualified laboratory that offers drinking-water copper analysis.

How to Reduce Copper in Drinking Water

There are two basic strategies for dealing with copper contamination:

Reduce the amount of copper entering the water
Treat the water after copper is already present

The best approach depends on the source and concentration.

Address the Plumbing Problem

If copper is entering the water because of plumbing corrosion, addressing the underlying plumbing problem can be more effective than relying solely on filtration.

Potential approaches include:

Correcting corrosive water conditions
Replacing problematic plumbing components
Addressing improperly installed plumbing
Consulting a qualified plumber or water-treatment professional

For a significant or persistent copper problem, identifying the source should be a priority.

Best Water Filtration Methods for Copper

Several residential filtration technologies can reduce copper.

1. Activated Carbon Filters

Certain activated-carbon filtration systems can reduce copper when specifically designed and certified for that purpose.

However, not every carbon filter removes copper.

Look for a specific copper-reduction claim rather than assuming that a generic carbon filter will address copper.

NSF certifies drinking-water treatment systems under NSF/ANSI 53 for specific health-related contaminant-reduction claims, including copper.

Advantages

Relatively affordable
Simple installation
No wastewater
Available as under-sink and other point-of-use systems
Can improve taste and odor depending on the filter

Disadvantages

Filter performance varies significantly
Requires regular cartridge replacement
Not every carbon filter is certified for copper

2. Reverse Osmosis

Reverse osmosis (RO) is another effective treatment technology for reducing copper.

NSF states that certified reverse osmosis systems can reduce copper to below the EPA’s 1.3 mg/L action level.

RO works by forcing water through a semipermeable membrane that reduces many dissolved substances.

Advantages of RO for Copper

Can substantially reduce dissolved copper
Treats multiple contaminants simultaneously
Widely available as an under-sink system
Useful when copper is only one of several contaminants of concern

Disadvantages

Higher initial cost than a simple carbon filter
Requires replacement filters and membrane maintenance
Produces some wastewater
Usually requires more installation space

If copper is your only concern, an appropriately certified carbon system may be simpler and less expensive.

If copper is one of many contaminants you want to reduce, an RO system can make more sense.

3. Specialized Filtration

In situations involving unusually high copper concentrations, specialized treatment may be appropriate.

The correct treatment depends on:

Copper concentration
Water chemistry
pH
Alkalinity
Corrosivity
Other contaminants
Household water consumption

For elevated or unusual contamination, consider having the water professionally evaluated rather than choosing a filter based solely on online marketing claims.

Recommended Water Filters for Copper

The most important recommendation is to buy based on verified copper-reduction performance rather than simply choosing a popular water-filter brand.

NSF’s current certification database specifically identifies products certified for copper reduction under NSF/ANSI 53.

NSF explains that certified filters claiming copper reduction undergo performance testing to verify the contaminant-reduction claim.

What to Look For

When evaluating a filter for copper, look for:

NSF/ANSI 53 copper-reduction certification
A specific copper-reduction claim
Published filter capacity
Replacement-filter availability
Appropriate flow rate
A certification listing for the exact model

Don’t confuse:

“NSF certified”

with:

“NSF certified for copper reduction.”

The second statement is what matters for this particular contaminant.

NSF’s current database provides a searchable list of products with copper-reduction claims.

Recommended Product Category #1: NSF/ANSI 53 Under-Sink Filter

For a household primarily concerned with copper, an NSF/ANSI 53-certified under-sink filter with a copper-reduction claim is one of the most straightforward options.

This provides treated water at a dedicated drinking-water faucet without requiring treatment of the entire house.

Recommended Product Category #2: NSF-Certified Reverse Osmosis System

If you want to address copper along with multiple dissolved contaminants, consider an NSF-certified reverse osmosis system.

NSF specifically states that certified RO systems can reduce copper below the EPA action level.

For RevOsmo readers, this is particularly relevant when copper is accompanied by contaminants such as lead, arsenic, fluoride, nitrate, or other dissolved substances.

Recommended Product Category #3: Refrigerator Water Filter

If your main concern is drinking and ice-making water from the refrigerator, look for a refrigerator filter with a specific certified copper-reduction claim.

Again, don’t assume a refrigerator filter removes copper simply because it has an NSF certification. Check the exact contaminant claim.

Does Boiling Water Remove Copper?

No. Boiling is not a recommended method for removing copper from drinking water.

Boiling kills or inactivates many microorganisms, but it does not remove dissolved metals such as copper.

In fact, evaporation can concentrate dissolved substances if water is boiled for an extended period.

If copper is the concern, use an appropriate filtration or treatment method instead.

Does Letting Water Sit Remove Copper?

Allowing water to sit is not a reliable treatment method.

If copper has dissolved into the water, simply letting it sit does not guarantee that the copper will be removed.

If your concern is copper that has accumulated in stagnant water inside household plumbing, flushing the plumbing may reduce exposure in some circumstances, but testing is the best way to determine whether the practice is adequate for your situation.

Does a Brita Filter Remove Copper?

Some water filters can reduce copper, but you should not assume that every Brita or other pitcher filter removes copper.

The correct approach is to check the specific model’s contaminant-reduction certification and performance claims.

For copper, look for a verified copper-reduction claim rather than relying on the general statement that a product is a “water filter.”

Does Reverse Osmosis Remove Copper?

Yes, properly certified reverse osmosis systems can reduce copper.

NSF states that certified reverse osmosis systems reduce copper below the EPA’s 1,300 ppb action level.

However, product performance varies, so consumers should verify the certification and performance claim for the specific RO system they purchase.

For households dealing with multiple contaminants, RO can be particularly attractive because it can address copper as part of a broader water-treatment strategy.

For more information about RO technology, see RevOsmo’s The Ultimate Guide to Reverse Osmosis Systems.

Copper vs. Lead in Drinking Water

Copper and lead are often discussed together because both can enter drinking water through plumbing.

However, they are different contaminants.

Copper is an essential nutrient at low levels, while lead has no known safe level of exposure.

Both can be affected by corrosion, which means household plumbing can play an important role in drinking-water quality.

If you are concerned about copper because of old or corroding plumbing, it may also be worth testing your water for lead.

RevOsmo’s guide to Lead in Drinking Water provides more information about lead sources, health risks, EPA regulations, testing, and filtration.

Frequently Asked Questions About Copper in Drinking Water

What is the EPA limit for copper in drinking water?

The EPA’s federal copper Action Level is 1.3 mg/L (1,300 ppb) when copper exceeds that concentration in 10% or more of applicable tap-water samples.

Can copper in drinking water make you sick?

High concentrations of copper can cause gastrointestinal distress, including nausea, vomiting, stomach cramps, and diarrhea. Long-term exposure to excessive levels can also affect the liver and kidneys.

Where does copper in tap water come from?

Copper in household drinking water commonly comes from corrosion of copper-containing plumbing materials, including pipes and fixtures.

Can you taste copper in drinking water?

High copper concentrations can produce a metallic or bitter taste. However, taste is not a reliable way to determine whether water exceeds regulatory levels. Laboratory testing is recommended.

Does a water filter remove copper?

Some filters do. Look for a specific copper-reduction claim, preferably certified under NSF/ANSI 53 or an applicable RO standard. NSF maintains a current database of products certified for copper reduction.

Does reverse osmosis remove copper?

Yes. NSF states that certified reverse osmosis systems can reduce copper below the EPA’s 1.3 mg/L action level.

Is copper in drinking water a problem for babies?

Elevated copper exposure can be a particular concern for infants and young children. If you have concerns about copper levels in water used for infant formula, consult your pediatrician and have the water tested.

Should I test my water for copper?

Testing is particularly worthwhile if you use a private well, have copper plumbing, notice metallic taste or blue-green staining, live in an area with known water-quality issues, or have reason to suspect plumbing corrosion.

Final Thoughts

Copper is an essential nutrient, but too much copper in drinking water can cause gastrointestinal distress and, with prolonged elevated exposure, potentially damage the liver and kidneys.

The EPA’s federal copper Action Level is 1.3 mg/L (1,300 ppb), and copper contamination is frequently associated with corrosion of plumbing materials.

If you’re concerned about copper, start with testing. Determining the actual concentration at your faucet is more useful than simply purchasing a filter based on a general contaminant-removal claim.

For filtration, look for a system with a specific, independently verified copper-reduction claim. NSF/ANSI 53-certified filters are available with copper-reduction claims, while certified reverse osmosis systems can also reduce copper.

If you’re researching other drinking-water contaminants, visit the RevOsmo Drinking Water Contaminants Explained pillar page.

Disclaimer: This article is for general educational purposes and is not a substitute for laboratory testing, medical advice, or professional water-treatment advice. Water-quality regulations, certifications, and product specifications can change. Always verify the current certification and contaminant-reduction claim for the exact filtration model you are considering.