Heavy metals often find their way into drinking water via old domestic pipes

The water company supplies clean water; the problem starts after that

Drinking water is one of the most strictly regulated foodstuffs in Switzerland, Germany and Austria. Waterworks supply water that complies with legal limits. But this regulation ends at the building’s boundary. What happens after that is the responsibility of the property owners.

And this is precisely where the problem arises. In many older buildings, water flows through pipes, fittings and taps that can leach heavy metals into the water. The longer the water sits in the pipes, the more metals are released. Anyone turning on the tap in the morning therefore often drinks water with a higher concentration of heavy metals than later in the day after flushing.

The main heavy metals found in tap water are lead, copper, nickel and cadmium. They enter the water in various ways and have different effects on the body.

Lead, copper, nickel, cadmium: where they come from

Lead enters drinking water mainly via old lead pipes. In Germany, these were installed until the 1970s, particularly in the north and east. Although lead pipes have been banned in Switzerland since 1904, they may still exist in older buildings that have not been renovated. Solder on pipe joints and older brass fittings also contain lead. In Germany, all remaining lead pipes must be decommissioned or removed by January 2026.

Copper comes from copper pipes installed in millions of households. Under certain conditions, such as with soft, acidic water, copper ions leach out of the pipe. A visible sign of this is greenish or bluish discolouration on fittings and drains. New copper pipes release particularly high levels of copper in the first few months after installation. Over time, a protective patina forms, which reduces the release.

Nickel is frequently released from chrome-plated or nickel-plated taps and fittings. Concentrations can be particularly high after the water has stood overnight. For people with a nickel allergy, even a low level of exposure in drinking water can be significant.

Cadmium is less common, but is found in galvanised steel pipes and older soldered joints. It accumulates in the body and primarily affects the kidneys.

The effects of heavy metals on the body

Not all heavy metals are equally dangerous, but even small amounts can have consequences if ingested continuously via drinking water.

Lead is the most critical substance. It accumulates in the bones and is broken down only very slowly. Children and pregnant women are particularly at risk. In children, lead impairs the development of the nervous system, learning ability and blood formation. As children consume significantly more water per kilogram of body weight than adults, the relative exposure is higher. In pregnant women, lead passes through the placenta to the unborn child and can enter breast milk. The Federal Environment Agency therefore recommends that infants and pregnant women should not drink water that has flowed through lead pipes.

At high concentrations, copper causes gastrointestinal complaints and can irritate the stomach lining. In small amounts, copper is an essential trace element, but the body’s requirements are usually already met through diet.

Nickel triggers symptoms in people with a nickel allergy. The limit has been lowered to 0.02 milligrams per litre in the EU to better protect allergy sufferers.

Cadmium accumulates in the kidneys with chronic exposure and can impair kidney function. Furthermore, it is suspected of disrupting bone metabolism.

What the limit values mean and where they are changing

The EU, Germany, Austria and Switzerland have set limit values for heavy metals in drinking water. The current limit value for lead is 0.01 milligrams per litre. From 2028, this will be halved to 0.005 milligrams in the EU. The limit for copper is 2.0 milligrams per litre, for nickel 0.02 and for cadmium 0.005 milligrams per litre.

Important to understand: these limits apply to water at the tap, not at the waterworks. If your home’s pipes leach heavy metals, the water in your glass may exceed the limits even though the waterworks is operating perfectly. And in Switzerland, drinking water is only regulated up to the property boundary. What happens after that is the owner’s responsibility.

A simple step that reduces contamination immediately: let the water run in the morning until it feels noticeably cooler. This flushes the stagnant water out of the pipes. When preparing baby food, authorities generally recommend letting the water run before use.

Why boiling water doesn’t help

Heavy metals are elements. They cannot be destroyed by heat, nor do they evaporate during boiling. Whilst the water becomes germ-free, the heavy metals remain entirely behind. If some of the water evaporates during boiling, the concentration of heavy metals in the remaining water actually increases. Boiling is therefore not a solution; in the worst case, it can actually worsen the contamination.

Which filters remove heavy metals

Anyone wishing to remove heavy metals from tap water needs a filter system that has been specifically developed and tested for this purpose. Three technologies are available.

Activated carbon block filters bind heavy metals through adsorption onto their porous surface. Lead and copper in particular are effectively retained when the activated carbon is used as a compressed block. Loose activated carbon granules, such as those found in simple jug filters, do not perform to the same extent. Minerals such as calcium and magnesium pass through the filter and remain in the water.

Reverse osmosis reliably removes heavy metals, as the fine membrane retains practically all dissolved substances. The removal rate is over 99%. However, this process also removes all minerals, and the system requires electricity and produces wastewater.

Multi-stage systems with mineral ceramics and activated carbon combine various natural filter media in a slow flow-through process. The ceramic layers retain particles and impurities, whilst the activated carbon binds dissolved heavy metals. Thorough adsorption is achieved through the long contact time between the water and the filter media. Laboratory-tested systems of this type filter heavy metals below the limit of detection whilst retaining the natural minerals in the water.

As with PFAS, the same applies here: not every filter that generally reduces pollutants is effective against heavy metals. Look for a laboratory test report that verifies the filter’s performance for specific heavy metals.

Our approach at MAUNAWAI

Our filter systems have been specifically tested for heavy metals in independent laboratory analyses. In a long-term trial conducted by the IIREC (International Institute for Resonance and EMC Research), it was demonstrated that the MAUNAWAI filter system reduces lead and mercury to below the limit of quantification. Copper and zinc are reduced to a fraction of the limit value. The research institute confirmed that the system has an “astonishing ability to remove inorganic and organic contaminants”, with particular effectiveness against heavy metals.

Our Pi technology works with 21 natural mineral ceramics and activated carbon. Pollutants are bound, minerals are retained, and water hardness is reduced to a pleasant level. No electricity, no chemicals, no waste water.

Whether as a Kini filter jug, a PiPrime gravity filter or a Peka home filter: all systems use the same filter technology. We publish the full test results under Science and Studies.

What you can do now

If you live in an older building, it’s worth finding out what material your water pipes are made of. Your landlord or property management company can provide this information. A professional water test will clarify the actual contamination levels at your tap.

Regardless of this: let the water run briefly in the morning before using it for drinking or cooking. And when choosing a water filter, make sure it has been proven to reduce heavy metals.

We’d be happy to advise you. Contact us or discover all MAUNAWAI systems at a glance.