Why does bathtub drain leaking occur when the tub fills lots of water?

[compiler]

I have a new bathtub installed. After I filled the tub much water and then drained it. I saw the drain leaking occurs under the tub. However, if the tub is filled less water, it does not have drain leaking. Is it because the much water the bathtub holds, the more water pressure the drain has? Can anyone explain it?

 

[phishfood]

Are you sure that it is the drain leaking, and not the overflow or a crack in the tub that only shows up when you fill the tub to the higher level?

 

[compiler]

Overflow should occures in the high area of the tub, right? I saw the water dripiing under the tub drain. The bathtub is new. It is unlikely crack.

 

[Mr_David]

the more water pressure the drain has? Can anyone explain it?

Possible ? yes. But often customers assume they know why or where it is leaking from and when I come to investigate it is entirely something else.

 

[compiler]

The plumber has come and said it is the overflow drain leak, He retighten the gasket. I am curious about why there is no leak on the tub top gasket area but on the plumb under the bathtub.

 

[frodo]

because water leaked out of the rubber and ran down hill due to gravity forces. then dripped, from the lowest point onto the floor.

 

[compiler]

I ever felt the rubber area but did not feel wet. The dripping was on the pipe under the tub. Do not know how it happened but it has been resolved anyway.