The water is undrinkable, we mainly got it for cold water and it has a terrible metallic taste like blood. We tried both reverse osmosis water and bottled water from the supermarket. The taste does not go away even after the disinfection function, which also does not work properly, since the manual says it passes 2 liters of water through the pipes, but it only heats and disinfects the water already inside the device's pipes. Apparently, the water comes into contact with something that gives it this taste and of course, it is very bad for your health. Returning it as it came. What a pity.

EDIT (1 week later): After searching A LOT online, it seems that this problem is present in many coolers, even large/professional models. It is due to the material that comes into contact with the cooling (metal plates inside on the inverter) and the minerals contained in the water. After discussing with a technician, he told me that the more premium coolers from other companies (e.g. Midea/Philips) have reverse osmosis filters inside but do not do re-mineralization of the water, they leave it without minerals, providing it directly after the membrane, exactly for this reason, because it created a plastic taste or sometimes an excessive iron taste (hence the blood taste). I went and bought a T-adapter for the reverse osmosis filter we have and added an extra supply at the point right after the membrane, which fills the water tank. If I use water from that point in the Xiaomi, the taste disappears and the water is drinkable. But if you make the mistake of using water from the stage where minerals are added back, the taste returns and the water is basically impossible to drink, it's so strong you can even smell it from a distance. This is the only reason I'm keeping it (I'm also raising the review to 2 stars from 1) because I solved the problem with a major workaround (I had to change the entire filter tap from single to double) and it also really helped my partner who wants hot water immediately. However, if you do not have the ability to provide water from reverse osmosis BEFORE the re-mineralization stage or any other enhancement after the membrane, then just FORGET IT because this device DOES NOT accept mineral water for cooling. Get one that already has filters inside, even though they are three or four times the price...