Ask a Water Research Scientist: Is It Safe To Drink Water From The Hot Tap?

Travellers often arrive at a new destination harbouring nagging anxieties. Will the taxi drivers try to rip me off? Can I put toilet paper into the toilet? And—the perennial favourite—can I drink the tap water?

In Iceland the answers are no, please do and absolutely, in that order. What comes out of Iceland’s cold taps is famously some of the purest water in the world. But what if—for some reason best known to yourself—you decided to drink the infamously eggy-smelling hot water?

We chatted to Dr. Arna Pálsdóttir, research project manager at Orkuveita Reykjavíkur, the company that supplies Reykjavík with water. So how does the hot stuff achieve that heady aroma in the first place?

“The hot water smells of rotten eggs because it contains hydrogen sulphide”

“The hot water smells of rotten eggs because it contains hydrogen sulphide. There are basically two hot water systems in the city, one of which gets hot water directly from geothermal wells within the city limits. The water in those wells naturally contains hydrogen sulphide, but not in dangerous levels of concentration.”

“We also take cold water from the ground, heat it up with geothermal energy and send it to the city. The cold water doesn’t contain hydrogen sulphide, but actually we add hydrogen sulphide to it. The reason we do that is to prevent corrosion in our pipeline and the radiator systems in homes. The hydrogen sulphide reacts with oxygen and provides a natural way to prevent corrosion.”

“I’d say that 90% of the time the hot water does fulfil drinking water standards. I mean it’s not classified as drinking water, but most of the time it fulfils the standards.”

So there you have it—straight from the scientist’s mouth. But if you decide to top your sulphate levels up with a glass of Icelandic aqua from the red tap, be warned that it can reach temperatures of up to 80 degrees Celcius! Maybe blow on it a bit first.

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