AC Condensate Leak Water Damage

An air conditioner pulls humidity out of your indoor air and that moisture has to drain somewhere. On most Michigan homes the air handler sits in a basement, a closet, or — more dangerously — in the attic, and the drip pan below the evaporator coil empties into a PVC condensate line that runs to a floor drain or outside the foundation. When that line clogs with algae biofilm, rust flakes, or drywall dust from a recent remodel, the pan backs up and overflows. On a typical July day in Macomb County, an AC can pull 15 to 20 gallons of moisture out of the air in 24 hours, so a clogged line can dump several gallons per day into whatever is directly below the unit. If the unit is in the attic, that water travels through ceiling drywall, R-49 blown-in insulation, and light fixtures before you ever see a stain.

Not necessarily. A small stain with no sag and a moisture reading under 16 percent in the drywall often dries in place with 1 to 2 air movers and a dehumidifier over 2 to 3 days, followed by a stain-blocking primer. The drywall has to come down when any of these are present: visible sag or a soft spot you can press with your finger, moisture readings above 18 percent after 48 hours of drying, visible mold growth on the back side that we confirm by cutting an inspection hole, or the insulation above is saturated and matted. We make that call with a Protimeter moisture meter after extracting standing water and running drying equipment, not by eyeballing the stain.

It depends on whether the carrier classifies the loss as sudden and accidental or as long-term seepage. A clogged condensate line that overflows overnight and soaks a ceiling is typically treated as sudden and accidental and covered under the dwelling coverage on a standard HO-3 policy from State Farm, AAA Michigan, Auto-Owners, Allstate, Farm Bureau, or Citizens. A slow drip that stained a ceiling over many months is almost always excluded as maintenance or gradual seepage. Adjusters look at three signals to decide: the size of the stain (small and fresh vs. large and ringed), whether there is mold on the back of the drywall (suggests the leak was not recent), and whether a prior claim or service record shows the system had been leaking before. Payment decisions are made by the insurance carrier after their own inspection.

Yes — those are two different trades. The HVAC technician clears the clog, adds a float switch, or replaces the drain pan so the leak stops. A water damage restoration company handles what the leak left behind: extracting standing water from the ceiling cavity, removing and disposing of saturated drywall and insulation, running structural drying equipment for 2 to 4 days, documenting the scope in Xactimate so your adjuster sees the same line items their software generates, and rebuilding the ceiling once moisture readings are back to dry standard. Skipping the drying phase is how ceilings grow visible mold on the attic side within 72 hours during July and August in Michigan.

A minor single-stain ceiling dry-in-place runs $800 to $1,600 before rebuild. A standard ceiling demo (8 to 16 square feet of drywall plus a section of wet blown-in insulation) runs $1,800 to $3,500 for mitigation. A larger attic-unit failure that saturates 40 to 80 square feet of ceiling, light fixtures, and a whole bay of insulation runs $3,500 to $7,500 for mitigation, plus rebuild. Rebuild (new drywall, primer, paint to match) typically runs $600 to $2,400 depending on ceiling height and paint match. These are 2026 Macomb County averages and every project is written from actual moisture readings and affected square footage, not guessed.

First, turn the AC system off at the thermostat so it stops producing condensate while the drain is clogged. Second, place a bucket or a tarp under the drip point — do not punch a hole in the drywall to drain it unless water is actively pooling on the ceiling and sagging (that is an emergency step to prevent a collapse). Third, photograph everything: the pan, the drain line, the stain, the damage below. Fourth, call your HVAC company to clear the clog and call a restoration company for the drying. Fifth, file a claim with your carrier and document the sudden-and-accidental nature of the loss (when you first noticed it, what you did to stop it).

Mold can begin colonizing wet cellulose and paper-faced drywall within 48 to 72 hours in warm weather, so a condensate leak that sits for a week in July is a real mold risk on the attic side of a ceiling. Most Michigan HO-3 policies include a mold sublimit (often $5,000 to $10,000) that only pays when the mold is a direct result of a covered water loss. If you maintain your system, report the leak promptly, and get the drying documented, the mold sublimit is usually in play. If there is evidence the system was leaking for a long time before you reported it, mold coverage is typically denied as a maintenance exclusion. We do not diagnose health effects from mold and we do not make habitability determinations — remediation scope is written to IICRC S520 and we defer health questions to medical professionals.

The AC itself is usually fine. The evaporator coil, blower, and refrigerant circuit are sealed and the condensate problem is a drainage issue, not a mechanical failure of the cooling system. Once the clog is cleared, a float safety switch is added (a $25 part that shuts the system off next time the pan starts to fill), and any corroded drain pan is replaced, the system is back in service the same day. The restoration work happens in parallel — you do not have to live without AC while the ceiling dries.