Hellobee Boards

I second thermos bottles. We had a bunch of the camelbaks and they all got mold in the lid. We have had the thermos ones for over a year with no issues.

@Ajsmommy: we use the same bottles. We hand wash and use munchkin straw and spout brushes to get into all the crevices. Where you insert the straw there are two rubbery pieces that pull out for a better clean

we hand wash, and occasionally I'll use a straw brush, but not usually, and we've never had mold. I'm not sure what we're doing right!

Ick. We've tried washing and drying straw bottles with q tips, but they still get moldy. If she's able to deal with a screw-top bottle, maybe try that instead?

FWIW, the mold never made anyone sick even though we didn't catch the problem right away

We had the same problem (although I definitely didn't wash every night). We got the nalgene one like @muffinsmuffins for the baby (now 2 and still going strong).
We got these for my 4 year old last year and no mold yet.
I get mold in every single kind of straw bottle so I've given up on them. I don't want to keep replacing straws or have to stick them in the fridge all the time.

https://www.amazon.com/Contigo-AUTOSEAL-Trekker-Bottles-Nectarine/dp/B00MVODNGG/ref=mp_s_a_1_4?ie=UTF8&qid=1536960116&sr=8-4&pi=AC_SX236_SY340_FMwebp_QL65&keywords=contigo+kids+bottle&dpPl=1&dpID=513VaAHanHL&ref=plSrch