On 24/06/2011 10:53 PM, Steve Pope wrote:

>
>>> Sounds like the sink is still plugged up.
>
>> I got the impression from the OPs description that it was the tailpiece
>> that is moving up and down, which would indicate a problem with the
>> drain itself. OTOH it could be that the tailpiece is moving up and down
>> in the trap. If that it the case, it might just need to be tightened a
>> bit more. Or...... a new collar and washer.
>
> Or the drain could be plugged up further down the line. Normally,
> even if the undersink trap pipes have lost integrity, there is
> no leak or very little leak until the drains start running slow.
>
> Basically you have two failures: slow or stopped drain, and a bad
> pipe. You need both failures to get a full-scale leak.


No. All you need is a bad pipe or a bad joint, and you are likely to get
a full scale leak every time water runs down the pipe.