Water has experienced something of a renaissance over the past couple of decades. It’s the perfect beverage, everyone – no exceptions – should be drinking as much as they can every single day in order to keep our bodies in top-notch working order…right?

Well, it turns out that might not be true, and you can have too much of a good thing.

The NHS recommends that adults should have six to eight cups glasses of liquids per day, which includes water, milks, tea, coffee, or anything else that’s sugar-free. There is no official guidance on the size of the glass, though, so clearly people’s consumption is going to vary.

In the United States, the National Academies of Sciences, Engineering, and Medicine advises an adult woman should consume 11.5 cups of liquid a day, while an adult man should have 15.5 cups.

The advice does include liquid contained in foods, though, which can be tough to parse.

The consensus around the world seems to be between 2 an 3 liters a day…but why?

We know that dehydration can be dangerous. The early hallmarks are feeling thirsty, dark, strong-smelling pee, feeling tired and/or lightheaded, and a dry mouth. If you have diabetes, sweat a lot, or are very young or very old, you may need to keep an extra eye on your hydration levels.

That said, there is such a thing as too much water. Known as water intoxication, the symptoms are nausea, vomiting, and an altered mental state that can lead to seizures, coma, and sometimes death.

The amount of water you have to drink to reach dangerous levels would vary based on a person’s size and lifestyle, though, but safe to say if you’re simply drinking water throughout a normal day, you should be fine.

Experts like nephrologist Karen Dwyer even agree that the 2-3 liters a day recommendation itself is more of a guideline than an actual rule, so don’t worry if you’re not able to totally stick to it.

“The best gauge of your hydration level is the color of your urine. You should aim for light yellow in color; if very dark then you’re dehydrated and need more water; if clear (like water) then you don’t need so much water.”

The 2-3 liter recommendation is for an average-sized person on an average day.

If you believe you have medical conditions or lifestyle particulars that would require you to consume more or less, you might want to talk with your doctor to decide what amount makes sense for you.