Silver ions for water tanks: a risk to your health?

Many campers swear by the use of silver products for water treatment. The antibacterial effect is supposed to keep the drinking water germ-free for a longer period of time and thus ensure clean drinking water. But is this really true? We get to the bottom of it!

In this article you will learn...

• ... what silver ions are and why they are used,
• ... whether silver in water is harmful to human health,
• ... the legal situation regarding silver in drinking water,
• ... how efficient silver is for water treatment,
• ... and what alternatives there are to silver ions in drinking water.

What are silver ions and what are they doing in the water tank?

Silver is a chemical element that belongs to the group of precious metals. Nowadays, it is used in a wide variety of areas - for example in electrical components, jewelry, cosmetics and clothing, as well as in the treatment of water.

When it comes to water treatment, we usually talk about silver ions (Ag+ ), i.e. tiny silver particles. They are said to have a microbicidal effect, as they are supposed to kill microorganisms and inhibit their metabolism.

Silver ions are therefore particularly popular in motorhome water tanks to keep the drinking water germ-free. Silver is available to buy for this purpose in a wide variety of forms - for example as balls, pads or mesh.

Are silver ions in the water tank harmful?

There are a number of studies on silver in drinking water and its potentially harmful effects on humans, animals and the environment. Most of the research has focused on aquatic organisms and a few on mammals. Studies on the effects of silver on humans are few and far between.

Whether silver is harmful to health or not depends in principle on various factors. These include, among others

• Type and form of silver (e.g. silver ions or nanosilver)
• Environment in which the silver occurs (e.g. air, earth, water)
• Concentration of silver

Scientific studies on the effect of silver on animals

Scientists began researching the effects of silver on various living creatures back in the early 20th century. It was discovered that the precious metal can cause serious damage to the health of some animals and in some cases even death.

Aquatic creatures such as minnows and rainbow trout are particularly sensitive to silver ^[1]. Frogs also showed changes in their metabolism. Invertebrates such as mayflies and amphipods are also susceptible. Several experiments on rats have also shown that the intake of large amounts of silver over a certain period of time can be fatal for these animals ^[2].

Scientific studies on the effects of silver on humans

There is very little and hardly any reliable data on the toxicity of silver in humans. However, it is assumed that silver is not dangerous to humans in the quantities in which it is usually found in drinking water ^[3].

It is also unclear how the results of research on animals and other organisms can be applied to us humans.

It is generally assumed that humans can consume up to 10 grams of silver over the course of their lives without fear of any harmful effects. The majority of the silver ingested is simply excreted again.

The only scientifically proven side effect of increased silver intake in humans is a condition called argyria. This is an irreversible, grayish or bluish discoloration of the skin. However, this is more of a cosmetic problem with no further harmful consequences.

There is no data to confirm a toxic effect of silver in the human medical fields of oncology, reproduction and development or neurology.

Legal situation regarding silver ions in drinking water

According to § 11 of the Drinking Water Ordinance, only those treatment substances that are included in a corresponding list from the Federal Ministry of Health may be used during the production, treatment and distribution of drinking water ^{[4] [5]}.

This list is maintained by the Federal Environment Agency and published regularly in the Federal Gazette. Silver has not been included in this list since 2017.

However, this directive only applies if the drinking water is passed on to third parties. As long as you use the water as an end consumer for your own consumption, you are still legally permitted to use silver ^[7].

The WHO, on the other hand, has not set an upper limit for silver in drinking water, as the concentration of silver in water does not usually make a significant contribution to the aforementioned upper limit of 10 grams ^[8].

However, it recommends that a maximum quantity of 0.1 mg/l should not be exceeded when using silver in drinking water treatment. With this concentration, a daily water intake of 2 liters would only result in 5 grams of silver even after 70 years, which is still far below the limit of concern.

Silver in water: how efficient is disinfection?

The WHO advises against using silver for disinfection. This is partly due to the partly unclear scientific situation regarding the toxicity of silver and partly due to its questionable efficiency.

According to studies, the effectiveness of silver in water treatment varies greatly and depends on the type of bacteria, germs, etc. The precious metal has proven to be particularly helpful in combating bacteria such as E. coli. However, here too, long contact times and a high concentration of silver are required for disinfection to be successful.

On the other hand, there are too few studies on its effectiveness against viruses and protozoa . The current data situation also does not allow a clear assessment of whether silver really kills bacteria or merely inhibits their growth.

Silver ions in drinking water: what alternatives are there?

We are also of the opinion that it is better to steer clear of silver ions for drinking water! In our range you will find various drinking water filters that are ideal alternatives.

The core of our filters always consists of activated carbon, which reliably removes numerous pollutants from your drinking water. Together with long-term travelers and permanent campers, we have put together various components in complete sets for water treatment in motorhomes.

These are suitable for refueling from the outside as well as permanently installed after the water tank and can be installed in no time at all. Our water filters are the ideal alternative to silver ions!

Here is an overview of our variants:

Silver ions in motorhomes: why is silver still used for the water tank?

Despite recommendations by the WHO and other public organizations against the use of silver in water treatment, it continues to be used by campers due to its alleged antibacterial properties. Manufacturers of various silver products argue that silver is a safe and effective way to keep water germ-free and that there are no dangers in its use.

Due to the ambiguous scientific data, it is difficult to completely refute these claims. In connection with the urgency of water treatment in caravans, it is therefore not surprising that many campers continue to use silver products.

However, as experts, we advise that silver should no longer be used for water tanks in caravans and that more suitable alternatives should be used instead.

Silver ions for drinking water: we say "hands off"

The use of silver in drinking water is highly controversial. On the one hand, there is no concrete evidence of negative effects of silver on human health. On the other hand, there is equally little evidence as to whether and to what extent silver actually improves the quality of water. In addition, silver is banned under the Drinking Water Ordinance.

We therefore say: stay away from silver and opt for more suitable alternatives.

FAQs

Are silver ions harmful to health?

This question cannot be answered clearly from a purely scientific point of view. The only thing that is certain is that the intake of large amounts of silver can lead to a condition called argyria. This leads to an irreversible, grayish or bluish discoloration of the skin. Other side effects of silver have not yet been clearly proven.

How long does water last in a tank with silver ions?

This depends on the manufacturer and usually varies between 6 and 12 months. However, we advise against relying on such information and recommend regular cleaning. Generally speaking, the longer the water sits in the tank, the greater the risk of germs and bacteria forming.

Are silver ions prohibited for water treatment?

The use of silver ions is only prohibited if you do not use the treated water yourself as the end consumer. As long as you use your motorhome for your own purposes, you can legally continue to use silver. However, if you wish to rent the motorhome to third parties, for example, silver is not permitted as a water treatment agent.

How can silver ions be removed from the water?

To remove silver ions from the water, it is best to use a high-quality drinking water filter.Activated carbon filters, reverse osmosis filters and ion exchange filters are particularly suitable. Silver ions are generally not a problem in German Tapwater , as they are only present in extremely low concentrations.

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