So my toilet started leaking from the base, so I turned the water off and took the toilet apart. The lip of the flange had broke and the wax ring was gone. Replaced the lip with a metal replacement plate, put quick Crete around flange so that we could have something to drill the bolts into something to hold the plate. Replaced bowl on new wax ring, and it holds water, no apparent leaks. Replaced tank - when my dad did this, he let water get all over the floor, then downstairs neighbor complained of water coming out of their bathroom ceiling vent/fan. I freaked out and stopped working on it.

Months later, bowl still is holding water, and no complaints of leaking downstairs, so I replaced the tank myself. A small amount of water got on the floor but I was very careful. Then I got the toilet operational. Yay! But then neighbor came upstairs screaming about the water out of her vent again.

There is a space between where the toilet meets the tile. Could this be the cause of the leak she is seeing out of her bathroom vent?

Pics of the gaps: enter image description here

enter image description here I market the water line with a marker hours ago, and the water is holding

  • FYI You might want to be careful, a water leak is a big deal for just the mold problem it creates. It cost well over $10,000 to fix our condo (I have no idea the total cost as it was paid for my our upstairs condo). We were in a hotel for 5 weeks while it was mitigated and repaired.
    – Ack
    Apr 11, 2020 at 18:13
  • 1
    Do a test. Tell you neighbor first that you want to do test. Remove the toilet and pour water down the pipe, careful not to miss and spill in space around the flange. Have your neighbor look for water coming through to their unit. If no water than you have eliminated the plumbing in the floor and it must be the toilet wax ring to flange connection or flange to pipe or some other water source. A photo of the flange would help us to see if it installed correctly. Have you eliminated the water supply pipes as a problem ?
    – Alaska Man
    Apr 11, 2020 at 22:47

1 Answer 1


Okay - where is the water coming from? Let's figure it out.

  • The only way it's coming from your toilet bowl is if the toilet is cracked. Since yout not showing water loss in the bowl - it probably isn't cracked.
  • It can be coming from a cracked waste line under the toilet if it was damaged during the flange replacement/repair scenario you described. But that's very unlikely based on what you described - so let's eliminate that.
  • It could be coming from the seal you replaced under the toilet but that has worked fine for months as you said, "Months later, bowl still is holding water, and no complaints of leaking downstairs". So that eliminates the seal.

Therefore given that the only times you've had complaints from downstairs is when you or your dad spilled a quantity of water on the floor during a repair of the toilet. The water had to have run across your tile and through the sub-floor around your toilet and waste pipe and out the downstairs vent.
The solution is simple enough. Clean as well as you can around the base of your toilet and apply a heavy bead of silicone bathroom caulk all around the perimeter of the toilet. Be sure to fill those gaps you're showing in the picture next to the flange bolts. That should do the trick.
Also, be very sure on future repairs to carefully scoop all water out of the toilet and tank prior to dismantling it.

  • I think the paragraph of the question said that it leaked downstairs when it was flushed,
    – Jasen
    Apr 12, 2020 at 4:32

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