Brown tap water - what does that mean?

If the tap water has an intense discoloration, which is usually very unappetizing. Where this staining comes from, and what it means, and whether there is a health hazard, is explained in this article.

Cause of discoloration

In general, a brownish to yellowish discoloration of the tap water indicates the presence of rust. The coloring comes from the iron and in some cases additionally from the manganese in the water and its corrosion products.

If the discoloration occurs after temporarily shutting off the water, this is normal for certain conduit materials. Due to the suddenly re-starting high line pressure of several bar rust particles, also from the solder joints of the water pipes, entrained.

For zinc-coated pipes, after a few years, when the zinc layer has peeled off, it may be possible for more iron to be released into the water. If the discoloration is more yellowish, it may also indicate additional manganese release, but you can not tell from the color alone.

Exceeding the limits

Damaged piping and galvanized piping may exceed the applicable limit of 0.2 mg / l of iron due to the increased release of iron into the water. The limit value for manganese in the Drinking Water Ordinance can also be exceeded.

This can be proven with a laboratory test of the water. Water suppliers often offer such tests free of charge in the case of discoloration.

Health hazard

In both cases, however, there is no health risk. Iron and manganese can be taken in very large quantities without causing any health problems.

Problems with devices

Some devices may cause technical problems by adding filters or components to the iron deposits. Boilers in particular are often at risk.


A secure remedy is only possible if the affected lines are replaced. In the case of galvanized lines, a protective layer can also be applied via metering devices, which prevents the release of iron into the tap water.

Tips & Tricks

When warm water is cloudy, this is usually not a technical or chemical problem - just the oxygen dissolved in the water. After a while, the water becomes clear again.

Video Board: How to Fix Your Water - Yellow or Brown Water (Tannin)