# White powder observed after boiling water in electric kettle for many weeks

I used my water kettle (metal ones, not the plastic ones) to boil my water. Usually, if I did not consume all the water in the kettle and the water was cold, I usually topup extra water to the kettle and turn it on to boil.

So, after many weeks of boiling in this way, I notice that there are white powder outside the kettle. (I notice that when the water is boil, some water was splashed to the outside of the kettle and I left those water splashed out to dry as time goes)

Is the white powder actually called fluoride? How do I tested it to verify if the white powder chemical is safe or not?

• I've never seen a kettle where that hasn't happened :) If you're concerned, clean it off. But take notice that it's actually coming out of the water. So drinking the water pure will mean you're getting more of it than you are when you've boiled it. – Brian Feb 7 '13 at 14:19
• As BBftw's answer says, the white powder is probably largely calcium carbonate. Chalk is calcium carbonate. So the white powder is probably no more harmful than chalk. – RedGrittyBrick Feb 12 '13 at 10:55
• You can clean out the kettle by boiling with some white vinegar. // By boiling the water you're boiling out carbon dioxide which makes the solution more basic. This makes mainly calcium carbonate precipitate. $$\ce{Ca(HCO3)_{2(aq)} -> CaCO3_{(ppt)} + CO2_{(gas)} + H2O}$$ – MaxW Nov 9 '15 at 3:34