20oz. Wide Flex Sip Lid Flask

I am extremely disappointed with this Hydro Flask lid design. I've owned this bottle for only a couple of months and have used it approximately 10 times. Recently, I noticed black residue around the mouthpiece area when I went to take a drink. That immediately raised concerns, so I decided to inspect the lid more closely. When I removed the silicone gasket, I was shocked to find a large amount of black buildup trapped underneath. The contamination was completely hidden during normal use and routine washing. The amount of buildup I found after such limited use is unacceptable for a product marketed as a premium water bottle. What concerns me most is that I first discovered the issue because black residue had already made its way to the area where I place my mouth to drink. Who knows how long I’d been drinking without knowing what was accumulating inside the lid. Even after extensive cleaning and scrubbing, the gasket remains stained and difficult to clean completely. A water bottle lid should not trap moisture and debris in hidden areas so easily, especially after only a handful of uses. Hydro Flask needs to redesign this lid or provide much clearer cleaning instructions. Based on my experience, I cannot recommend this lid design.