Ah, That Age-Old Dispute Over Who’s Responsible When One Condo Unit Causes Damage in Another

March 2026

Tags: Dispute Resolution, HOA Common Elements

An HOAleader.com reader asks: “We live in a condo building in New York. A unit owner on the third floor discovered black mold in her utility closet that was traced to a leak from the HVAC in the unit above her (the top floor). So far, she has paid for the mold inspection and remediation in her unit to the tune of $30,000.

We suspected the unit above her was also filled with mold, and the building paid for the inspection report so we could see the results. (We suspected that if the owner paid, he wouldn't share the report with the board.)

Sure enough, the inspector found mold, which the owner must remediate. He's refusing, saying he doesn't believe his HVAC unit is the cause of all the mold. We have now agreed to share the report with him and have given him five days to address the problem.

The question is: If there is indeed mold behind the walls in his unit, is that the responsibility of the building to remediate? What if we can prove his HVAC caused the problem? His downstairs neighbor is concerned that if the mold is left untreated while we fight about who pays, it'll spread again into her unit. Also, if mold is behind the walls, is the building's responsibility? It seems we'd have to reimburse the third-floor unit owner for remediating mold behind her walls.”

This is one-hundred percent a state law and governing document issue. So here our experts from various states two questions: What are your general rules for how this should shake out? Also, did this board act properly in paying for the inspection and in its actions toward the owner suspected of being the source of the problem?”

Question 1: What are your general rules for how this should shake out?

In Colorado, when there's damage caused by water intrusion, Melissa Garcia, a retired former shareholder at Altitude Community Law PC in Lakewood, Colo., who provided advice and counsel to Colorado associations in all areas of community association law and continues to be a resources for communities, advised her clients to take three steps that are generally applicable to condos everywhere.

“First, figure out what was damaged,” she advises. “Then, see what the condo's documents say as to who's responsible and who typically repairs the damage. And third, figure out whether negligence or insurance responsibilities shift the cost to someone else.

“Typically, who pays has nothing to do with who's responsible for the damage,” says Garcia. “In the reader's example, the water could have come from the owner's AC unit, but that owner could have also been in no way negligent. Why are we assuming that because the water comes from the owner's unit that they should pay for it? That's the big thing. It's not where the water comes from.”

The question in Florida is also whether someone was negligent, not where the damage originated. “Who's responsible always comes to negligence,” according to Matthew Zifrony, who advises homeowners and condo associations at Tripp Scott, a Ft. Lauderdale law firm, and who has also served as the president of a 3,000-home association. “For example, I moved to a high-rise condo—I'm now a condo owner rather than a single-family homeowner.

“In the first few weeks, we did all the renovations to our unit, and one of my AC units leaked and caused damage below,” he recalls. “Legally, who's responsible? It all comes back to negligence. If I didn't do anything wrong and I had no reason to believe the AC unit would leak, I'm not legally responsible. That's what insurance is for.

“On the other hand, if the AC company had someone flush the system and they did it wrong, they'd be responsible,” says Zifrony. “In another example, if a report showed that a water leak by the unit above was because the owner above tended to overflow their bathtub, it's pure negligence.

“Moving away from legal responsibility would be the moral responsibility,” he adds. “My wife pointed out that if this happened to us, I'd hope the owner above us would pay. She said to me: ‘Don't we want to show the same consideration to the owner below?' I agreed with her. So I took the opposite approach of Florida law. I didn't want to pick a fight with the building or the owner below.

“So in Florida, step one is determining the damage and whether there's negligence,” concludes Zifrony. “You want to know what the damage is, particularly if it's mold because there could be health and safety concerns. When you do the report, that'll often tell you where the damage came from, and that tells you the negligence part.”

That's not the case in Michigan. “Generally, if there's mold, Michigan condo law doesn't mandate any repair and replacement responsibilities,” says Kayleigh Long, a member with Hirzel Law in Farmington, Mich., which represents hundreds of community associations throughout Michigan. “That's all within the documents.

“Anything within the walls tends to be the association's responsibility,” adds Long. “But a lot more associations are including provisions in their documents saying that if owners did this damage within the perimeter walls, they're going to be responsible.

“So if the owner's HVAC was responsible for causing damage that resulted in mold, as in the reader's example, in Michigan, the board would likely say, ‘OK this is our responsibly to repair, but you're going to have to pay the cost,'” says Long. “We're seeing more of these provisions that essentially say, ‘If you caused it, you're responsible.'”

A newish Connecticut law also puts the responsibility of the party causing the damage, even if there's no negligence. “In Connecticut, the Common Interest Ownership Act has some provisions for this,” reports Patricia A. Ayars, founder of Ayars & Associates in Glastonbury, Conn., who has been practicing association law for more than 30 years.

“There's a new statute effective Oct. 1, 2025,” she explains. “Under the new law, if a unit owner in a common interest community makes any addition, alteration, or improvement that increases the community's common expenses, such as its repair or insurance costs, the owner must be assessed for those expenses.

“In other words, those owners are automatically liable for the increase in common expenses that their action caused,” explains Ayars. “The law doesn't even specify that the unit owner who took the action has to be the current unit owner. If damage came from that unit, the costs are put back against the current unit owner. So if this owner installed an HVAC, the association could go back and charge that owner for the damages caused.”

Question 2: Did this board act properly in paying for the inspection and in its actions toward the owner suspected of being the source of the problem?

Long thinks this board was right to foot the bill to investigate the problem. “That's especially true for something like this to determine what's going on, the scope of the problem, and how to tackle it,” she states. “We might tell a board, ‘We think you're going to have to get some sort of report because, based on what we know so far, we don't know where you should start. Or you may think this person is responsible, but it may actually be someone else.'”

“It's perfectly fine for the board to say it's going to get the inspection,” says Long. “Some documents will allow the board to assess that cost back to the responsible co-owner. Other times, the condo may have to eat that cost, but it might end up being worth it. Where it's impacting two or three, or maybe more, units, getting a grasp on the entire situation is smart, especially where the association might have responsibility on repairing and replacing as well.”

Connecticut would even allow the board to enter the unit above. “In Connecticut, the condo can enter an owner's unit and correct any condition that causes danger or damage to another unit or common element,” states Ayars. “This situation the reader describes would be enough to go into the unit.

“I'd also give the owner the report the board commissioned to put pressure on them,” she says. “I'd say, ‘Hey, your HVAC is the cause of the damage, and we're going to charge you back for the repairs, or the neighbor downstairs is going to sue you. I think you should know about the report that the expert we consulted with provided.”

Zifrony is also on board with the condo asking an expert to investigate and provide a report, but the question of who pays for the investigation will be document driven. “Always look to the association documents,” he says. “In most instances, they'll say you're responsible for damage to other units. They might also say the owner is responsible only for actual repairs, not for reports. In those cases, the board can't impose the costs of the report on the owner. If the documents are broader and say ‘responsible for repairs,' not ‘actual repairs,' there could be an argument that the owner is also responsible for paying for the report.”

It's also a document question in Colorado. “There's a cost to have your engineer go out and see where the water is coming from,” says Garcia. “In the documents we drafted, we said the condo can charge those investigation costs back to owners.

“But we'd sometimes advise boards to eat the costs for those,” she adds. “Or we'd advise clients to amend the documents to say that if there's any question about water intrusion and it turns out the water comes from one owner, that owner will be charged for that investigation cost—not necessarily the damage, but the investigation. But only if that's in the documents.”

Reprinted from HOA Leader