If you have copper pipes in your home, it’s likely you’re drinking copper. While it has long been believed that this material is the most suitable for plumbing, it might have some drawbacks. In this article we’ll explore how copper affects your health, how much copper is allowed in drinking water, and how to remove it from your tap water.
Copper is one of the most widely used metals in the world. It was the first metal ever to be worked with by humans, and has remained in use throughout the ages due to its many useful properties (such as electricity conduction, heat conduction, and malleability).
Because it is so versatile, you will find copper everywhere: art, buildings, computers, cars, cookware, etc. It is used to make electrical wires, roofing and plumbing, as well as industrial machinery. Copper is also used in nutritional supplements and in fungicides used in agriculture.
There are two main ways copper ends up in your tap water.
The first way copper ends up in tap water is the run-off from agricultural land into the rivers and streams from which drinking water is extracted. Copper has antibacterial and fungicidal properties, and is therefore used in agriculture (especially on vines, fruit trees, and vegetables such as potatoes and tomatoes) to prevent certain diseases. Copper is also present in animal feed, particularly that given to pigs. It is therefore heavily present in slurry (a mixture of urine and excrement from farm animals that is sprayed on fields as fertiliser).
When copper-containing slurry or fungicides are sprayed on fields, the copper seeps into the soil and ends up in water sources. These methods have long been used, but the modern intensification of animal farming has caused an excess of copper in the soil, and this excess ends up in our water.
Areas closest to agricultural land or areas where there is intensive animal farming tend to have higher levels of copper in groundwater and surface water.
The second reason copper ends up in your tap water is because it flows through copper pipes and pipe fittings as well as brass faucets (brass is a mix of copper and zinc). Copper oxidises when it comes into contact with oxygen (present in water). As a result, it leaches into the water. If the water is soft (slightly acidic), it will corrode faster and result in higher levels of copper in the water.
The amount of copper in your drinking water depends on several factors:
In the right quantities, copper is an essential nutrient.
The body needs copper to form and maintain connective tissue and bones; it is an important component for a strong immune system and for blood clotting. Copper is involved in the transport of oxygen throughout the body, and even determines hair colour (pigmentation). It plays a role in cardiovascular health and hormonal balance. The body uses copper to produce enzymes that protect cells from free-radical damage.
Copper deficiency has been linked to mental disorders, impaired central nervous system, and fragile bones. However, it is rare that we do not get enough copper. The risk is that we get too much.
If too much copper is consumed (even relatively small amounts), this can lead to stomach and intestinal issues such as nausea, vomiting and diarrhoea. Over time, an excess intake of copper damages the liver, kidneys, and nervous system; it can even be fatal.
The recommended daily intake of copper for adults between 19 and 50 years old is 900 micrograms (or 0.9 milligrams). The tolerable upper intake of copper is 10,000 micrograms (10 milligrams).
The World Health Organisation’s Guidelines for Drinking Water Quality established a safe limit for copper content of 2 milligrams per litre (mg/L) of water.
These guidelines also state:
“The guideline value for copper is also based on short-term exposure but is intended to protect against direct gastric irritation, which is a concentration-dependent phenomenon. The guideline value may be exceeded, but there will be an increasing risk of consumers suffering from gastrointestinal irritation as the concentration increases above the guideline value.”
The European Union’s Drinking Water Directive follow’s the WHO’s recommendation and sets the limit for copper in drinking water at 2 milligrams per litre.
The legislation adds the following note:
“Compliance samples for certain chemical parameters, in particular copper, lead, and nickel, shall be taken at the consumers’ tap without prior flushing. A random daytime sample of one litre volume is to be taken. As an alternative, Member States may use fixed stagnation time methods that better reflect their national situation, such as the average weekly intake by consumers, provided that, at the supply zone level, this does not result in fewer cases of non-compliance than using the random daytime method.”
The Dutch Water Decree limits the amount of copper to 2 mg/L.
According to a report by the RIVM, additional measures are necessary in order to control the amount of copper that ends up in Dutch water from various sources (agriculture being the most difficult one to reduce).
In 2012, 90% of the 7.7 million households in the Netherlands had copper piping. Since then, around 400,000 new homes have been built. In many of these, plastic water pipes may have been used instead of copper, because plastic is cheaper and easier to install. These pipes might not leach copper into the water, but they release other harmful chemicals.
In France, water legislation follows EU guidelines and limits the quantity of copper to 2 mg/L.
However, the most recent national study of public health shows that French citizens have higher blood levels of heavy metals, including copper, compared to adults in the rest of Europe.
This could be due to the amount of metals in tap water. According to the consumer association Que-Choisir, more than 75% of water samples are of “very bad” quality, due to pollution from human activity (such as pesticides and nitrates) as well as components from water pipes (such as PVC, lead, and copper).
If you want to know more about the quality of your water, you can head to the interactive map on Santé France’s (Ministry of Health and Prevention) website: https://sante.gouv.fr/sante-et-environnement/eaux/eau
Italian legislation on drinking water limits the amount of copper in tap water to 1 mg/L, half the amount specified in the EU’s Drinking Water Directive. However, a study by the University of Bologna and the University of Naples found that all water samples taken in regions across Italy measured above the limit.
Water in Italy is managed on a region by region basis. In order to find out more about water in your region, the Ministry of Health recommends getting in touch with your local water distribution company or checking your municipality’s website.
The United Kingdom’s legislation on drinking water quality limits the amount of copper to 2 mg/L. It also notes that “Compliance samples for chemical parameters including copper, lead and nickel must take the form of a random daytime sample of one litre volume taken at a consumer’s tap without prior flushing.”
According to the latest report on drinking water quality by the Department for the Environment and Rural Affairs (DEFRA), 99,99% of samples were within this limit.
Ireland’s legislation on drinking water matches the EU’s limit of 2 milligrams of copper per litre of water. It also states that “The value applies to a sample of water intended for human consumption obtained by an adequate sampling method at the tap and taken so as to be representative of a weekly average value ingested by consumers and that takes account of the occurrence of peak levels that may cause adverse effects on human health.”
The Irish Environmental Protection Agency’s latest report on the quality of public drinking water found that only two samples of the 1022 taken in 2022 exceeded this limit. However, around 200,000 people in Ireland are supplied by private wells that don’t always meet the standard.
The United States’ Environmental Protection Agency sets the limit for copper in drinking water to 1,3 milligrams per litre.
Since 2013, the Environmental Working Group has been collecting data on tap water quality in the United States. Head to their website and insert your zip code to find out how much copper (and other chemicals) are in your water: https://www.ewg.org/tapwater/
While copper is an essential mineral, it’s possible to have too much of a good thing, especially when drinking water legislations allow more copper in one litre of water than an adult’s recommended daily intake.
If you want to make sure you don’t ingest too much copper, there are several ways you can tackle the problem. Reverse osmosis, ion exchange, and distillation systems all remove copper from your tap water… and so does the ZeroWater filter.
Do you want to make sure your tap water is free from copper? ZeroWater 5-stage filters remove 100% of copper from tap water. They also filter lead, limescale, glyphosate, chlorine, PFAS, and more. Take a look at our web shop and enjoy pure, clean drinking water.
