Heavy metals in drinking water: limit values, origin and filters
Lead, copper, nickel: which heavy metals occur in drinking water, which limit values will drop in 2028 and 2030 and which filter has been proven to retain lead.
Heavy metals are metals with a density of more than 4.5 to 5 g/cm³. In drinking water, the German Drinking Water Ordinance sets a limit value for ten of them; for lead, 0.010 mg/l applies, and from 12 January 2028 half of that. The official measurements from 2022 paint a clear picture. For chromium, mercury, antimony and selenium, all samples complied with the limit value. For lead and nickel, a combined 124 tests exceeded it. Both come from the domestic plumbing. An activated carbon block filter at the tap targets precisely this point.
This guide classifies 10 regulated metals by their origin. It lists the limit values, including the 3 reductions up to 2036, and checks 3 filtering methods against the measurement data for 1,678 filters.
What heavy metals are
Heavy metals are a group of metals with a high density. The most common criterion is a density of more than 4.5 to 5 g/cm³. They include gold, silver, platinum, mercury, iron, copper, lead, zinc, chromium and uranium. They occur naturally in rock and enter the water cycle through leaching and industrial processes.
In the body, the group splits into two halves. Iron, copper and zinc are trace elements and essential to life in small quantities. Lead, cadmium and mercury, on the other hand, accumulate and damage the kidneys, blood formation and the nervous system. Infants and young children are the most sensitive because their nervous systems are still developing.
For lead, the Umweltbundesamt (UBA, German Environment Agency) sets out the strictest restriction in its drinking water recommendations. According to these, water from lead pipes is always unsuitable for pregnant women, infants and children up to the age of six. The recommendation is dated 23 July 2025.
Raw water or domestic plumbing: 2 pathways
The Drinking Water Ordinance sorts the chemical parameters in Annex 2 according to precisely this question. Part I lists 18 substances whose concentration usually remains constant in the distribution network. Part II lists 16 substances whose concentration can increase in the drinking water installation.
| Origin | Metals | Where the contamination originates |
|---|---|---|
| Raw water, Annex 2 Part I | Chromium, uranium, mercury, selenium | Rock and groundwater, tested at the waterworks |
| Plumbing, Annex 2 Part II | Lead, copper, nickel, antimony, arsenic | Pipes, soldered joints and taps in the building |
The Umweltbundesamt has its own term for the second group: material-derived contaminants. Lead, copper and nickel are the three key parameters of this group. Their concentration depends on how long the water stands in the pipe and which materials have been installed.
The distinction determines the countermeasure. The waterworks tackles a metal from the raw water. For a metal from your own plumbing, only an intervention in the building helps: replacing the pipes or a filter at the point of use.
Limit values in the Drinking Water Ordinance
Ten metals have a limit value under Annex 2 of the Drinking Water Ordinance. For three of them, the value will fall by 2036. The values apply at the consumer's point of use, i.e. at the tap.
| Metal | Limit value | When it drops | New value |
|---|---|---|---|
| Copper | 2.0 mg/l | unchanged | 2.0 mg/l |
| Iron | 0.200 mg/l | Indicator value, Annex 3 | 0.200 mg/l |
| Aluminium | 0.200 mg/l | Indicator value, Annex 3 | 0.200 mg/l |
| Manganese | 0.050 mg/l | Indicator value, Annex 3 | 0.050 mg/l |
| Chromium | 0.025 mg/l | 12 January 2030 | 0.005 mg/l |
| Nickel | 0.020 mg/l | unchanged | 0.020 mg/l |
| Lead | 0.010 mg/l | 12 January 2028 | 0.005 mg/l |
| Arsenic | 0.010 mg/l | 12 January 2036, new systems 2028 | 0.004 mg/l |
| Uranium | 0.010 mg/l | unchanged | 0.010 mg/l |
| Selenium | 0.010 mg/l | unchanged | 0.010 mg/l |
| Antimony | 0.005 mg/l | unchanged | 0.005 mg/l |
| Cadmium | 0.003 mg/l | unchanged | 0.003 mg/l |
| Mercury | 0.001 mg/l | unchanged | 0.001 mg/l |
With arsenic, it pays to read the small print. The value of 0.004 mg/l applies to all water supply systems from 12 January 2036. Systems that go into operation from 12 January 2028 must already meet it from that date. For existing systems, the value remains 0.010 mg/l until 11 January 2036. Anyone who reads 2028 as the year for arsenic has overlooked the transition for existing systems.
Iron, aluminium and manganese are listed in Annex 3 as indicator parameters. They indicate taste, colour and turbidity. An exceedance points to a problem in treatment or in the network; more on this in the guide Rust in tap water.
What the official measurements show
Every 3 years, the Bundesministerium für Gesundheit (Federal Ministry of Health) and the Umweltbundesamt report on drinking water quality. The current report was published in February 2025 and covers the years 2020 to 2022. It includes water supply areas in which more than 1,000 m³ per day is distributed or more than 5,000 people are supplied.
| Metal, year 2022 | Tests | Exceedances | of which from the plumbing / compliance rate |
|---|---|---|---|
| Nickel | 14.581 | 63 | 29 99.57% |
| Lead | 14.573 | 61 | 19 99.58% |
| Arsenic | 10.813 | 26 | 0 99.76% |
| Copper | 14.042 | 16 | 3 99.89% |
| Uranium | 9.225 | 16 | 0 99.83% |
| Cadmium | 13.057 | 2 | 1 99.98% |
| Chromium | 9.843 | 0 | 0 100.00% |
| Mercury | 8.694 | 0 | 0 100.00% |
| Antimony | 10.352 | 0 | 0 100.00% |
| Selenium | 8.695 | 0 | 0 100.00% |
Two metals carry the burden. In 2022, nickel and lead together accounted for 124 exceedances, all eight others together for 60. Across all three reporting years, only chromium complied with the limit value in every sample. Selenium recorded two exceedances in 2020, mercury and antimony two each in 2021.
The trend for lead over the reporting period moves within a narrow band. In 2020 there were 70 exceedances in 13,705 tests, then 84 in 14,405 in 2021, and 61 in 14,573 in 2022. For nickel, the figures of 70, 69 and 63 are at a similar level.
The statistics come with a caveat. Testing was carried out against the Drinking Water Ordinance of 2001, which was still in force during the reporting period. For 9 of the 10 metals, the values have remained identical. Only for chromium was the old limit value, at 0.050 mg/l, twice as high as today.
The Umweltbundesamt clearly attributes the findings. Exceedances for lead are considered an indication of lead pipes still present in the drinking water installation or of taps that do not comply with the recognised rules of technology. For cadmium, exceedances occur very rarely and exclusively in drinking water installations, often after users themselves have installed unsuitable taps.
Lead in drinking water and the 2026 deadline
Lead accumulates in the body and is excreted only slowly. The limit value of 0.010 mg/l has been binding since 1 December 2013; from 12 January 2028 it will fall to 0.005 mg/l. This halves the permissible content within 15 years.
Lead has been replaced as a pipe material since 1973. The phase-out varied greatly from region to region. In parts of southern Germany, a ban was already in force in 1878, and in Bavaria and Baden-Württemberg its use ended with the 19th century. In northern and eastern Germany, by contrast, lead pipes were laid in some areas until the early 1970s. Anyone living in an old building there bears the higher risk.
Since 13 January 2026, the deadline has passed. § 17 of the Drinking Water Ordinance requires the operator of a water supply system to remove or decommission lead pipes and sections of them by the end of 12 January 2026. After the deadline has expired, the operator provides the public health office with written or electronic proof of compliance.
| Provision in § 17 TrinkwV | Contents |
|---|---|
| Paragraph 1 | Removal or decommissioning by the end of 12 January 2026 |
| Paragraph 2 | Extension of the deadline if an order was placed with a registered specialist company before the cut-off date |
| Paragraph 3 | Extension until 12 January 2036 at the latest for owner-occupied single-household systems |
| Paragraph 4 | Obligation to provide proof to the public health office after the deadline |
| Paragraph 5 | Obligation to inform consumers, in text form from 13 January 2026 |
| Paragraph 6 | Obligation for water suppliers and installers to notify the public health office |
Tenants find their lever in paragraph 5. If the operator learns of lead pipes in the building, they inform the consumers supplied without delay and then state the expected date of the renovation. From 13 January 2026, they also declare in text form that they have fulfilled the obligation or that an extension of the deadline applies.
The extension under paragraph 3 has narrow limits. It applies to building water supply systems and private water supply systems if the water serves only the operator's own household and damage to the health of the regular users can be ruled out. If minors, pregnant women or women of childbearing age move in, the operator reports this to the public health office without delay. In the event of a change of ownership, the deadline ends one year after the transfer.
Identifying lead pipes
Visible pipes can be checked with 4 simple tests. Information can be provided by the building owner, the property management and the caretaker. A measurement is carried out by an approved testing laboratory.
| Feature | Lead | Other materials |
|---|---|---|
| Sound when tapped | dull | Steel and copper ring clearly |
| Scratch test with a coin | soft material, scratch remains | Copper and steel stay smooth |
| Magnet | falls off, lead remains non-magnetic | Steel attracts the magnet |
| Routing | curved, flexible, bulging soldered joints | straight runs, screwed connections |
The surface of unpainted lead pipes is silver-grey, and the diameter is often irregular. The year of construction remains a clue: houses built before 1973 are possible locations, and in northern and eastern Germany also those from the early 1970s.
Copper, nickel and cadmium from the plumbing
Copper, nickel and cadmium typically come from the building itself. Their common feature: the concentration rises the longer the water stands in the pipe.
At 2.0 mg/l, copper has the highest limit value of all regulated metals. It is a trace element; in high doses it irritates the stomach and intestines. An epidemiological study by the Umweltbundesamt is available on infant nutrition. If the limit value of 2.0 mg/l that applied at the time is complied with as a weekly average, infants are protected from liver disease. The prerequisite is freshly drawn water for preparing powdered milk.
Nickel topped the exceedance statistics in 2022, with 63 cases in 14,581 tests. The limit value is 0.020 mg/l. The source is usually chrome-plated taps with an intermediate nickel layer. Nickel mainly triggers allergic skin reactions; details can be found in the guide Nickel in drinking water.
At 0.003 mg/l, cadmium is at the lower end of the scale and damages the kidneys, liver and bones. In practice, it plays a minor role: in 2022, 2 out of 13,057 tests exceeded the value, and none in either 2020 or 2021. Where it occurs, an unsuitable tap is often the cause.
Uranium, arsenic and chromium from the raw water
Uranium, arsenic and chromium come from rock and reach the water before the waterworks. Their concentration usually remains constant in the domestic plumbing.
Uranium enters groundwater from geogenic sources and has a limit value of 0.010 mg/l. In 2022, 16 out of 9,225 tests were above it, which corresponds to 99.83% compliance. Arsenic also comes from the subsoil and has a limit of 0.010 mg/l, with 26 exceedances in 10,813 tests. Notably, both metals recorded zero cases from the drinking water installation in 2022.
Chromium comes from industrial wastewater and from coatings on taps. The limit value of 0.025 mg/l will fall to 0.005 mg/l on 12 January 2030, i.e. to one fifth. In the reporting years 2020, 2021 and 2022, all of the approximately 9,850 tests per year complied with the value. At that time, however, testing was carried out against the old value of 0.050 mg/l, which was twice as high. Only the measurements of the coming years will show whether the record also holds against 0.005 mg/l from 2030.
How measurements are taken: S0, S1 and S2
Under the Drinking Water Ordinance, lead, copper and nickel require a special procedure. It is based on the Umweltbundesamt's sampling recommendation of 18 December 2018. Staggered stagnation sampling provides 3 samples of 1 litre each.
| Sample | Timing | What it shows |
|---|---|---|
| S0 | after flushing until the temperature is constant | Quality of the drinking water supplied |
| S1 | after 4 hours of stagnation, 1st litre | Drinking water installation including the draw-off tap |
| S2 | immediately afterwards, 2nd litre | Drinking water installation only |
Between S1 and S2, the tap remains open so that the full volume gets into the samples. A stagnation time of at least 2 hours is also permissible. The measured value is then extrapolated to 4 hours using the factor 4/t, i.e. doubled for 2 hours. The normalisation assumes a linear increase in concentration over the standing time.
The limit value is considered exceeded as soon as one of the three samples is above it. This exact rule is set out for lead, copper and nickel in Annex 2 of the Drinking Water Ordinance. If the value normalised to 4 hours exceeds the limit value, a repeat sample with exactly 4 hours of stagnation follows for confirmation.
Filtering lead out of drinking water
At the tap, 3 of the common filtering methods are suitable for lead. The benchmark is the NSF/ANSI 53 test standard. The abbreviations stand for the National Sanitation Foundation (NSF) and the American National Standards Institute (ANSI). A certified filter reduces lead from 150 µg/l in the test water to no more than 5 µg/l in the outflow. Until 2019 the threshold was 10 µg/l; since 2020 the halved value has applied. The test water thus contains ten times the American action level of 15 µg/l.
Activated carbon block filter
The activated carbon filter in block form combines two operating principles: mechanical fine filtration retains particulate lead, while the internal surface of the activated carbon binds dissolved substances. Sintered blocks achieve a much finer structure than loose granules. The guide Risk of germ growth in jug filters advises against jug filters with a loose fill. Changing the cartridge at the intended interval determines its effectiveness.
Reverse osmosis filter
Reverse osmosis forces water through a membrane with pores in the nanometre range. Lead is retained along with almost all other dissolved substances, including uranium and arsenic. The price for this is three disadvantages: the membrane also retains calcium and magnesium, which is why remineralisation follows. On top of that come flushing water and energy consumption. For a single contaminated parameter, the process is oversized.
Ion exchange filter
The ion exchanger swaps lead ions for sodium ions. The resin has a limited capacity and then needs to be regenerated. The practical catch: exhaustion remains invisible to the user, as most devices lack an indicator mechanism. Against particulate lead from pipe deposits, the process is inherently weak because it targets dissolved ions.
| Method | Operating principle | Weakness | Everyday use |
|---|---|---|---|
| Activated carbon block filter | Fine filtration and adsorption | Cartridge change needed at set intervals | high, directly at the tap |
| Reverse osmosis | Membrane separation | Mineral loss, flushing water, electricity | medium, with storage tank |
| Ion exchange | Ion exchange for sodium | Exhaustion remains invisible | medium, regeneration needed |
What the measurement data say about certified filters
In 2023, a review by experts from the US environmental agency examined the question empirically. In Water Research, Tang and colleagues evaluated 23 studies with 1,678 filters certified to NSF/ANSI 53: 1,486 tap-mounted filters, 167 jug filters and 25 under-sink filters. In field use, 1,512 of 1,528 filters reduced lead to or below the certification value, i.e. 99%. In the laboratory, only 91 of 150 filters, or 61%, managed this.
There is an explanation for the difference: laboratory filters were often operated under conditions beyond their approval. The paper names four factors as causes of failure. The first is lead concentrations above the test threshold of 150 µg/l. The second is particulate lead whose form and size differ from the test water. The third is lead phosphate nanoparticles below 200 nm. The fourth is operation that deviates from the instructions. In practice, this means that a certified filter delivers what the certification mark promises, as long as the replacement interval and operating conditions are observed.
What filters achieve against the other metals
For lead, the body of studies is robust; for the other metals, it is thinner. The operating principles determine the range of effectiveness.
| Metal | Activated carbon block | Reverse osmosis | Ion exchange |
|---|---|---|---|
| Lead | proven under NSF/ANSI 53 | proven under NSF/ANSI 58 | dissolved fractions |
| Copper | partly, testing per product | broadly effective | dissolved fractions |
| Nickel | partly, testing per product | broadly effective | dissolved fractions |
| Uranium and arsenic | low | broadly effective | depending on the resin |
| Iron and manganese | particles: yes, dissolved: low | broadly effective | dissolved fractions |
Two notes belong here. First, a certification to NSF/ANSI 53 always applies to a single product and a single substance. A seal for lead applies to lead alone. Second, the release of the measured retention rates for the Alb Filter cartridges is still pending. A percentage is therefore deliberately left open here.
If you suspect contamination from uranium or arsenic in the raw water, the quickest way to clarify it is through the water supplier. The waterworks' analysis values are public; the procedure is described in the guide Measuring water quality.
Immediate measures at the tap
3 steps take effect immediately, even before any purchase. The first two are free of charge and cover the most common cases.
Running the water is the first. After a night, the water has been standing in the pipe for 8 to 12 hours. The metal content rises over the standing time. The connection lies in the Umweltbundesamt's normalisation formula: for half the standing time, the laboratory multiplies the measured value by 2. In practice, this means letting the tap run until the temperature is constant before the water goes into the pot or the glass.
Asking the water supplier is the second. The waterworks' analysis values cover the metals from Annex 2 Part I, i.e. chromium, uranium, selenium and mercury. However, they say nothing about the domestic plumbing.
A measurement according to S0, S1 and S2 is the third step. For lead, copper and nickel, only this provides reliable information. Approved testing laboratories carry it out; the list is kept by the relevant state office. For households with infants or during pregnancy, it is the most sensible first step in old buildings. If it reveals contamination, the next decision is between replacing the pipes and a drinking water filter at the point of use.
Related to this topic
Active Plus+ cartridge – designed for heavy metals
The Active Plus+ filter cartridge is designed for pollutants and heavy metals. Among other things, it reduces lead, copper and nickel from the domestic plumbing and leaves the minerals in the drinking water.
Frequently asked questions
How do heavy metals get into water?
Via two routes. Chromium, uranium, arsenic and selenium come from rock and reach the groundwater from geogenic sources. Lead, copper, nickel and antimony leach from pipes, soldered joints and taps and are therefore called material-derived contaminants. In addition, there are inputs from industry and agriculture.
Are heavy metals harmful?
It depends on the metal and the dose. Iron, copper and zinc are essential to life in small quantities. Lead, cadmium and mercury, on the other hand, accumulate and damage the kidneys, blood formation and the nervous system even at low concentrations.
Can lead be filtered out of water?
Yes. Filters certified to the NSF/ANSI 53 test standard reduce lead from 150 µg/l to no more than 5 µg/l. In field use, 99% of 1,528 tested filters achieved this. The permanent solution remains replacing the lead pipe, which § 17 of the Drinking Water Ordinance has required anyway since January 2026.
Does boiling help against lead?
Boiling actually increases the concentration. During boiling, water evaporates, the lead stays behind and the content per litre rises. Boiling is only effective against bacteria and germs.
Are lead pipes magnetic?
Lead is non-magnetic; a magnet falls off it. On steel pipes, it sticks. As the sole indicator, however, the test is of limited use, because copper is also non-magnetic. Only in combination with the sound test and the scratch test does the identification become reliable.
What limit value applies to lead from 2028?
From 12 January 2028, the limit value falls from 0.010 mg/l to 0.005 mg/l. It is considered exceeded as soon as one of the three samples S0, S1 or S2 of the staggered stagnation sampling is above it.
Did lead pipes have to be removed by 2026?
Yes. § 17 paragraph 1 of the Drinking Water Ordinance required removal or decommissioning by the end of 12 January 2026. Extensions are possible if an order has been placed with a specialist company, and for owner-occupied single-household systems until 12 January 2036 at the latest.
Does shower water contain heavy metals?
Shower water is drinking water from the same installation and carries the same metals. However, absorption through the skin is low; the risk arises from drinking. A filter where drinking water is drawn off therefore targets the most effective point.
How much iron is allowed in water?
Iron has an indicator value of 0.200 mg/l under Annex 3 of the Drinking Water Ordinance. Higher values show up as a metallic taste, brownish colouring and turbidity. In terms of health, iron is considered the most harmless of the metals discussed here.
Does a water filter remove all heavy metals?
No, the range depends on the method. Reverse osmosis has the broadest effect and also captures uranium and arsenic. An activated carbon block filter is designed for lead and particulate load. Each certification applies to one product and one substance, so it is worth checking the test certificate.
How often should you have your water tested?
A measurement makes sense when you move into an old building from before 1973, when lead pipes are visible and when babies or pregnant women join the household. After that, it only needs repeating after the plumbing has been renovated. The water supplier is responsible for ongoing monitoring.
Sources
- Trinkwasserverordnung of 20 June 2023, BGBl. 2023 I No. 159 — with § 17 on lead pipes and Annexes 2 and 3
- Report on drinking water quality in Germany 2020 to 2022, Umweltbundesamt (German Environment Agency), February 2025 — with 14,573 lead tests and 61 exceedances for 2022
- Lead in drinking water, Umweltbundesamt, as of 23 July 2025 — with the 12.01.2026 deadline and the regional differences
- Umweltbundesamt sampling recommendation of 18.12.2018 — with the staggered stagnation sampling S0, S1 and S2
- Tang, Lytle, Achtemeier and Tully, Water Research Volume 244, 01.10.2023 — with 1,678 filters tested and 99% meeting the target in the field
- List of devices certified for lead reduction, NSF — with the test standards NSF/ANSI 53 and NSF/ANSI 58
- Epidemiological study on copper in infant food, Umweltbundesamt — with the weekly average of 2.0 mg/l as the threshold
