1 year old and water

My lo turned one last week and I’m still trying to figure stuff out. He’s drinking whole milk now but I’m still unsure about how much he should have I usually give him maybe 24 ounces in a day maybe 30. Now with water I was told that they need more water like 40 ounces a day?

I asked my lo’s doctor but I just asked of I should give him more water and he just told me yes. This is through email btw so I messaged back how much water to be exact. Do they need that much water?