Slab Leak, Two Years of Staining, and a Mold Sublimit
An insured owns a 1998-built Phoenix home under an HO-3 with Dwelling A of $420,000 on a replacement cost basis, a $2,500 all-peril deductible, and a $10,000 mold sublimit. On March 3 a copper supply line under the slab fails and water runs for roughly 30 hours before discovery. Emergency mitigation and tear-out bills $27,000. Damaged flooring and cabinets are $41,000 replacement cost and $29,000 actual cash value. Mold remediation bids $14,500. The insured mentions the same line had sweated and stained drywall for two years and had been patched once. The carrier's inspector finds advanced corrosion and an older patch. The insured wants the full $82,500 billed. The contractor's invoice also includes $6,000 to replace a rotted sill plate that the inspector says predates the March 3 event.
1. Determine coverage item by item and compute the correct payment(s). Show the arithmetic.
Read the worked answer
Covered event. Sudden accidental discharge from a plumbing system is a covered peril. A failure followed by about 30 hours of running water qualifies; it is not the slow-leak scenario the policy excludes.
Excluded portion. The two years of sweating, staining, and the prior patch are constant or repeated seepage over 14 days, which is excluded. The rotted sill plate belongs to that excluded history and is not payable. The $6,000 comes out of the invoice.
Mold. Remediation of $14,500 is subject to the $10,000 sublimit, so $10,000 is payable and $4,500 is not. Mold resulting from a covered water loss is treated under the endorsement, not as a separate occurrence.
Deductible. One occurrence, so one $2,500 deductible.
Replacement cost calculation. Covered items: mitigation/tear-out $27,000 + building damage $41,000 + mold capped at $10,000 = $78,000. Less $2,500 = $75,500 on a completed-repair basis.
If repairs are not yet complete, pay actual cash value first: $27,000 + $29,000 + $10,000 = $66,000, less $2,500 = $63,500, with $12,000 held back as recoverable depreciation. Document the holdback in the letter so the insured knows how to claim it.
2. The insured disputes the allocation and says the whole leak was one event. How should the adjuster support and communicate the position?
Read the worked answer
The concept to explain is that allocation follows causation, not convenience.
Build the evidence. Photograph and map the damaged areas: fresh saturation from the March 3 release versus chronic staining, efflorescence, and the older patch. Obtain the plumber's report on the failure mode. If the sill plate's condition is contested, a licensed contractor's written opinion or a limited engineering report (cost against a $6,000 dispute is easy to justify) settles it.
Explain in writing. Use a coverage letter that lists each item, the amount claimed, the amount allowed, the reason, and the policy language relied on. State the mold sublimit explicitly and note the excluded long-term seepage. Invite the insured to send any evidence that the sill plate damage was fresh.
Do not depreciate the mold. The sublimit caps it; taking depreciation on top of a cap usually produces an indefensible number.
Handle the deductible once. A common dispute is a carrier applying the deductible per trade or per room. One occurrence means one deductible; say so plainly.
Keep the undisputed money moving. Issue the $63,500 or $75,500 promptly. Withholding the whole claim to win a $6,000 argument is precisely what turns a valuation dispute into a bad-faith allegation.
3. Six weeks later the insured reports new mold in the same hallway and a second water bill spike. What does this change about the claim and the adjuster's obligations?
Read the worked answer
This is new information, not a re-opened argument, and it should be treated as a new loss report with a fresh investigation.
Re-examine the cause. A second spike suggests the repair did not stop the source, or a second line is failing. Get the plumber back out and confirm what was actually repaired in March. If the March repair was incomplete, the carrier may owe additional mitigation and re-remediation of the same occurrence rather than a new deductible.
Apply the sublimit against the occurrence, not the calendar. If this is the same March 3 occurrence, mold payments already made reduce the remaining $10,000 available. If a genuinely new break occurred, it is a new occurrence with its own deductible and its own sublimit, and the policy language controls.
Mitigation duty. Tell the insured in writing to mitigate now: shut off the supply, dry the area, and keep receipts. Reasonable mitigation costs are generally payable even where the underlying damage outcome is disputed.
Repeated loss pattern. Two failures on the same line within a year invites a conversation about the policy's repeated-seepage exclusion, the condition requiring reasonable maintenance, and whether the insured must replace the remaining copper. Do not threaten non-renewal as leverage; state the coverage reasoning and let underwriting handle the rest.