@Natalie she’s not having more then 8 oz but I’m having to offer it throughout day instead of just at meals because she’s not having milk as much so I’m worried about dehydration.
Breastmilk changes for what baby needs so if she needed more hydration it would adjust accordingly. As long as she's having wet nappies I wouldn't be worried.
This sounds like what has happened to my son. He’s now almost a year but around 10months slowly started to drop feeds. Keep offering the breast and see if she will take it during the day. We only did water during meals as well. As long as she’s getting lots of iron riches foods during meal times and dairy products like cheese and yogurt then she will be okay.
Three milks feeding plus three meals is plenty. Your milk adjusts to their needs. Just keep water to mealtimes until 1 year.
They shouldn't be having LOTS of water. Less than 8oz a day at this age and don't replace milk with it. They need the milk for nutrition and water fills them up.