I would like to see what happens in a rainstorm. The water from the flat roof may not be draining into the single skinny downspout we can see but may be flowing over the side and down the brick wall.

As well, the brick trim under the grey siding and the stone trim may not project enough to keep the downpour off the brick. Hence the efflorescence. An onsite inspection should be able to spot the sources of excess water. Effective water shedding details are often overlooked in both the design and build processes.

This much efflorescence is not normal in a new build. (It’s not normal in an old build). There is water getting into the walls and a lot of it. Do you have an hoa or do you own that wall?

I would also try to tackle any repairs before that building next door gets build, as it will easier to access the wall and maneuver any equipment needed.

I agree with Worthy. Rainwater is entering at the horizontal siding-to-brick joint because siding or flashiing doesn't properly overlap the top of the brick.

I enlarged the photo and it looks like the joint needs self-adhered flexible flashing from under the siding to over the top of the brick covered with metal counter flashing.

As for how serious efflorescence can be (other than the appearance), it depends on the climate. In cold climates susceptible to freeze-thaw cycles, it can eventually result in cracking and/or spawlling of the face brick.

I would be interested to see the siding to brick detail in the contract documents.

I’m in the south where freeze thaw isn’t a concern but have a client that noted (moderate) efflorescence over the last couple of years that finally presented itself as a full blown leak on the first floor. Turn out they hadn’t caulked under a door sill on the second floor which let water blow under the sill and into the brick veneer in every storm.

Agree with others. The fact that there doesn't appear to be efflorescence on the left side under the outdoor patio (which has a larger overhang above the brick) points to water likely getting in from above.

Lived through a horrible experience with a condo that did not have the proper roofing membrane on top (too thin--holes developed when workmen walked on roof, icicles speared through it), wrong mortar in the brick facade (too strong of a mortar mix--caused facade to crack), and lack of adequate attic ventilation (moisture rose up from condo units and condensed in area under roof). Lawsuit and million dollar+++ in repairs. Unbelievably ugly. Less than 30 units in all, and everyone on the second floor had to move out because the roof and second-floor ceiling had to be removed. Beautiful building, and most owners had their unit inspected when they purchased. They did not, however, have the building itself inspected when they purchased their units, so the building's garage and roof were not inspected by owners.

In our situation, the developer controlled the HOA until XX of the units were sold. Then control of the HOA was turned over to the owners.

Get inspectors in there now and have experts inspect. The clock is ticking. Do not trust developer/builder if they are still involved. You need an independent appraisal of situation.