You can cook with distilled water and nothing bad happens. It boils, it hydrates rice and pasta, and it leaves no mineral film in the pot. What it does not do is taste like anything, and using it for everything means carrying jugs home forever to solve a problem that is usually cheaper to fix at the tap.
What actually changes in the pot
The clearest gain is scale. Boil hard tap water repeatedly in a kettle or a stock pot and the minerals stay behind as a chalky crust; distilled water leaves nothing. Against that, cooks who taste carefully often report that vegetables and rice cooked in distilled water come out slightly flatter, and stock made with it can taste thinner. Seasoning still works normally, since you are adding the salt yourself. For most dishes the difference is small and easily corrected in the seasoning.
Where it genuinely helps and where it does not
Distilled is worth it for anything that boils water and holds it: kettles, steam ovens and humidified proving cabinets all last longer without mineral. It is not automatically right for coffee and espresso. Many espresso machines detect the water level electrically and need some conductivity to work at all, and manufacturers commonly specify filtered water within a mineral range rather than distilled. Check the manual before filling an expensive machine with the wrong water on principle.
The cheaper way to get the same result
If you have switched to distilled for cooking because the tap tastes of chlorine or leaves scale on everything, treat the supply rather than buying the fix by the jug. Read your utility's report first: every community water system publishes an annual Consumer Confidence Report, and the EPA maintains a finder that will bring yours up. Then choose the equipment that matches the finding. Our cities with the best tap water page shows how widely local supplies differ before anyone treats them.
Questions people ask about can you cook with distilled water
Does distilled water boil faster than tap water?
Not to any degree you would notice in a kitchen. Boiling time is set by the pan, the heat source and the volume, not by the mineral content of the water.
Will cooking with distilled water strip minerals from food?
Some minerals leach into any cooking water, distilled or not, which is one reason cooks keep the liquid for stock or sauces rather than pouring it away.
Is distilled water safe for making baby formula?
It is commonly used because it contains almost nothing dissolved. Follow your pediatrician's guidance and the formula manufacturer's instructions on preparation.