drinking water turning yellow?

[tigerlill]

Pretty strange problem here - I give my 2 year old filtered water in his sippy cup, but it sometimes changes to a murky, yellow colour. Which seems to make my son hyper and won't sleep until 1am. I do check/clean/ change the water and cup when I can, I just don't understand what is turning the water yellow.
To make things worse, a family member is blaming me for this and thinks that I am putting something in my son's water! (This family member is known to blame other people for things that aren't their fault) But I don't like being accused of something that I haven't done.

I would be greatful if someone could tell me what's going on.

Family member is putting something in.

You're saying you put clear water in and it mysteriously changes colour? Does the same happen in a different sippy cup? Have you tasted the yellow water? Does it only happen when family member is around?

What do you use to filter the water?

Murky yellow could be e.g. a soluble vitamin tablet - but that could be quite unhealthy for a two year old.

I have tried a different cup, but my son didn't like it - but the water didn't colour. No, I haven't tried it, but I will if it happens again and the family member is around a lot of the time.

I don't use anything like that.

I think you need to throw the cup away. There's no way of knowing what it is and it could be dangerous, the plastic could be degrading. What cup is it?

Take a sample of the yellow water and the cup to the police and get it analysed.

To the police??

It's probably just food particles from his mouth backwashing into the cup. I would throw the cup away and use other ones. I'm sure you'll find another that he likes.

Just do a food diary for a week.
Yoghurt backwash? Carrots? Tomato?

What type of cup, what colour is it and are you cleaning the seal properly?

At two, can't you switch to a plastic beaker (and plastic table cloth ) for meal times and a standard water bottle for out and about?

Thankyou for everyone's help. It turns out that it was backwash from the foods he was having. (I gave him some carrot corn sticks, then checked the water later on, and found some food particles and the water has changed colour.) The family member who blamed me for it has been told and hasn't said anything else about the issue - but is stomping around like a bear with a site head. :)