Two years ago I had my roof re-shingled and the chimney bricks repointed. This year I notice black liquid leaking out from the bottom of the chimney. What's weird is the black liquid is also leaking outside of the chimney perimeter. ONLY the water heater uses the chimney to vent. Then even stranger thing happened, the black liquid is now leaking out of one of the ducts attached to the furnace. From what I can see the duct is not even attached to the chimney it is running at least 6 feet away from it.

Through several weeks of observation, I know it's not cause by the rain, it's been sunny and I continue to see black liquid leak everyday so I know it's cause by condensation by water heater.

Is this even creosote? I was able to clean it up with just a moist rag, it wasn't sticky at all.

  • Unless your water heater burns wood, it's not creosote if the water heater is the only thing using the chimney. Now if there's also a fireplace that burns wood but you didn't mention as it's built-in to the chimney, you might have some creosote...but soot and condensation from a small gas appliance using a very oversized flue would be a better bet so far. – Ecnerwal Jun 10 '20 at 1:39

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