Published on: 28.10.2019

Information produced by Finnish Environment Institute

What if my tap water is defective?

Nainen juo vettä lasista

The quality of tap water is usually consistent, but sometimes you may notice a weird colour or funny taste in it. What causes it, and what should you do about it?

Iron, manganese and other deposits that accumulate in pipes over time may sometimes be carried away with water and end up on your tap, making the water look brown. While this is not a health risk, you should not drink the water or use it for washing your clothes. Letting the tap run for a while usually helps.

Mineral deposits may end up in the water during repairs or maintenance operations of the water distribution network, which cause pressure fluctuations. When water pipes are cleaned from time to time, deposits are removed and collected, but some of them may get as far as your tap.

Air bubbles may also make the water look grey and turbid after maintenance operations. In a glass, these air bubbles rise to the surface and the water clears from the bottom up.

Letting the tap run for a while also helps with a musty taste in water that has not been used for a long while. If the musty taste is there all the time, the usual culprit is the building’s water pipes, which need cleaning or replacement.

If you suspect a serious defect in the water or you believe it has made you ill, contact your municipality’s health inspector. Such causes as a pipe breakage may have contaminated the water, and it may be necessary to boil it or stop using it altogether. The municipality will tell you what to do and also inform other residents if necessary.