Thats what the ?? was.
As I understood the writeup about how it works, the capacitance makes the receiving pin slower to reach the high, and the processor detects this.
In theory if the touchpad is in water, then it should also impart some capacitance.
The spa pools I dealt with used AC and a opamp to detect that it was getting 'shorted out' by the presence of water, and would therefore allow the heating elements to work.
The other option is to use ADC and detect a lower voltage when it gets 'shorted out' by water.
In this case you wouldn't necessarily want the internal pull-ups turned on.
Mark