The noise you're hearing is air escaping through the valve, this allows air back into the bottle so water can flow out.
- To help alleviate this noise, pull the air valve up and allow it to fall back into position. Repeat up to 10 times.
- We also recommend thoroughly cleaning the inside of the cap with warm, soapy water and also pushing the little silicone valve to the side, and cleaning around it.
- Another trick is to try and avoid inverting the bottle when drinking from it as the air will struggle to escape when liquid is sitting on the valve.
Please be aware that while the above instructions will help to reduce the noise, some noise may still occur as air in the bottle needs to escape.