Semi-circle cutout in Toto Drake tank

[albatross83]

Is this normal or a defect? If it's normal, what's the purpose?

 

[Gary Swart]

It's normal. That's the way they are made.

 

[Sponsor]

 

[SamC]

Maybe it's there to allow free passage of air in and out of the tank as the water level changes.

 

[albatross83]

Thanks, good to know it's not a defect. I think you're probably right about the air flow... After installing and testing, this thing flushes FAST.

 

[Gary Swart]

The tank lid fits pretty firmly all the way around the tank, so while it might not make a truly air tight seal, it would be enough to prevent air from entering the tank fast enough for the water to release for the flush. Like holding your finger over one end of a drinking straw.