Small puddle basement floor

Over several days of inspecting there’s been a small puddle of water surrounded by condensation in the middle of the concrete basement floor of a 1914 solid brick house.

Interesting, water surrounded by condensation. HMMM.

Welcome Mark. Do you have a question?


seems to be coming from furnace, see the rust stains below the furnace


I’d like to know how that was identified?

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That was a bad picture.
This picture shows the puddle and its 6 ft away from the furnace

Plus the furnace hasn’t run in a month.

Though it maybe related

The condensate drain for the furnace is tied into a nearby drain with no air gap or trap

It’s an existing small puddle of water in middle of the floor.
There is a sanitary tub a few feet away.
Thanks for all your help.

That would explain the rust under the furnace. Boilers, especially cast iron, are common to leak inbetween sections when shut down for a while.


The furnace may not be running but the AC may have been. Typically condensation leaks when the AC is running is typically one of three issues. The drain line is clogged or disconnected or the evaporator coil is dirty preventing the condensation from trickling down to the gutter or tray at the bottom.


Thank you all for the information
The AC unit is being replaced as part of the real estate agreement.
I’ll make sure the HVAC technician has this information.

Even with the furnace not running did you remove the bottom cover to verify no active leaking from any condensation collected in the lower cabinet? … Look straight up for any plumbing? … water seeping up from the cracks under the home? Did you scan it with a thermal imaging camera? Run hot water in floor drains before you scan. Did you dry it and see if it reappears? Any negative sloping of the soil at the exterior? Voids near the foundation for water to enter? Any downspouts terminating at the foundation? If there’s no explanation, you might recommend to have the floor drains scoped for damage. Or recommend a contractor drill a hole in the area to determine if water is coming from under the house.


I think all the basics have been covered above. This may be of interest. Is the water originating from this crack?


I believe the AC hasn’t been operating for some time.
Past 24hrs no water was used in house.
3 days ago this puddle was there.
It has been raining.
The downspouts are tied into the old Terra cotta and don’t know where they drain too.
The chimney has no crown and is wide open.
Only the hot water flue uses it.
Put a moisture meter on the bottom by the old (cemented over) clean out and got high moisture readings.
The condensate line is plummed direclt into floor drain and is 2 ft from that crack.
Note pictues

Hydrostatic pressure
Soil water percolating past the perimeter drainage field and under the slab.
Slab cracks.
Likely settling columns.

Sounds good
Thank you