Update- Still Unresolved: Plumbling Help Please!!! A challenge stumped plumber
We would greatly appreciate it if someone could help us figure out our toilet dripping issue. Even willing to send you a gift card if your solution works out 
Here's the issue:
We just finished renovating our upstairs bathroom. The one bathroom in the main hallway, was just cosmetic work-changing vanity/tiling/from tub to shower. The master bathroom we changed from single to double vanity, and enlarged the shower and changed existing tub to freestanding one.
No issues with bathrooms prior to renovation. After renovating-our toilet in main bathroom has a dripping sound that lasts up to 10/15 minutes after flushing. We did reuse the same toilet-Toto Ultramax immediately after renovating. The dripping sound appears to come from underneath the toilet. The dripping after flushing is about once every 5-10 seconds after flushing, fading and slowing in frequency over the next 10-15min before finally stopping. The toilet never flushes by itself despite the dripping sound.
At first, we though it was the toilet being reused, so now we've bought a new Gerber one. Same issue with the new toilet. The general contractor and plumber have returned and have no idea what is going on. There doesn't appear to be any dripping/leaking onto the main floor ceiling, nor does there appear to be any leaks around the toilet or anywhere else. When the plumber came, he reviewed the toilet/flushing/added water (no food dye was available) and the result was always the same dripping sound even if the toilet wasn't flushed manually but a lot of water into the toilet bowl to simulate a flush so that the flush did occur.
Any thoughts/suggestion!!! Any help greatly appreciated as we're not using our new bathroom with this new annoying dripping sound.
Update:
What we've tried so far: We've tried pouring hot water down the toilet bowl, these definitely a lot less dripping sounds to almost minimal. It would appear that when pouring water down the toilet bowl, the bowl fills up but to a low level, hence no dripping. However, when we flush, it would appear that the toilet bowl fills and even after flushing, the water in the bowl continues to recede until it seems to hit a certain level and then stop receding which coincides with the cessation of the dripping sound. What would make the toilet bowl water continue to recede after flushing?

Here's the issue:
We just finished renovating our upstairs bathroom. The one bathroom in the main hallway, was just cosmetic work-changing vanity/tiling/from tub to shower. The master bathroom we changed from single to double vanity, and enlarged the shower and changed existing tub to freestanding one.
No issues with bathrooms prior to renovation. After renovating-our toilet in main bathroom has a dripping sound that lasts up to 10/15 minutes after flushing. We did reuse the same toilet-Toto Ultramax immediately after renovating. The dripping sound appears to come from underneath the toilet. The dripping after flushing is about once every 5-10 seconds after flushing, fading and slowing in frequency over the next 10-15min before finally stopping. The toilet never flushes by itself despite the dripping sound.
At first, we though it was the toilet being reused, so now we've bought a new Gerber one. Same issue with the new toilet. The general contractor and plumber have returned and have no idea what is going on. There doesn't appear to be any dripping/leaking onto the main floor ceiling, nor does there appear to be any leaks around the toilet or anywhere else. When the plumber came, he reviewed the toilet/flushing/added water (no food dye was available) and the result was always the same dripping sound even if the toilet wasn't flushed manually but a lot of water into the toilet bowl to simulate a flush so that the flush did occur.
Any thoughts/suggestion!!! Any help greatly appreciated as we're not using our new bathroom with this new annoying dripping sound.
Update:
What we've tried so far: We've tried pouring hot water down the toilet bowl, these definitely a lot less dripping sounds to almost minimal. It would appear that when pouring water down the toilet bowl, the bowl fills up but to a low level, hence no dripping. However, when we flush, it would appear that the toilet bowl fills and even after flushing, the water in the bowl continues to recede until it seems to hit a certain level and then stop receding which coincides with the cessation of the dripping sound. What would make the toilet bowl water continue to recede after flushing?
Last edited by stars78 on Dec 23rd, 2020 11:31 am, edited 1 time in total.