new vanity faucet leak

[mkbrech]

I recently installed a new Moen faucet in my bathroom. I used a standard 6" tailpiece extension to connect the Moen tailpiece to the P trap. The tailpiece and the tailpiece extension is plastic and the P trap is PVC. I used standard plumbcraft washers at both the top and bottom of the tailpiece extension. I did not use any tape or dope on any of the threads. After connecting everything and ensuring proper fit and tightness and careful not to overtighten or strip the threads, I ran the water multiple for extended periods of time to include filling the basin. I did this over a period of hours and there were no leaks or signs of water around any of the connections. In the morning, I checked the pipes and there was water leaking from the tailpipe extension washers...totally confused as to where the water is coming from since the sink has not been used since I tested it last night. Water does not seem to be leaking down from the top in the area of the flange and/or the pivot rod (they are dry) Any help is appreciated.

 

[johnjh2o]

Did you use plumbers putty on the flange? That will prevent water from leaking between the flange and the sink.

 

[mkbrech]

No, I used silicone because Moen said not to use plumbers putty...there appears to be no leakage when I fill the basin and there is no leakage when I run the water for long periods of time...but I suppose I can try it with plumbers putty and see if that is the cause. Is it possible that there is residual water leakage that is left over in the pipe and that is why it only leaks after sitting dormant at night?