Formula or decision rule
visible affected area = sum of each measured patch area; compare with about 10 ft² and all non-area escalation conditions- Measure rectangles or conservative bounding areas without disturbing material.
- Ten square feet is an approximate EPA decision point, not a guarantee that DIY cleanup is suitable.
- Correct the moisture source as part of the response.
EPA scope screen
| Finding | Area result | Planning response |
|---|---|---|
| Limited visible area | less than about 10 ft² | review EPA homeowner steps and other conditions |
| Larger visible area | about 10 ft² or more | consult EPA remediation guidance/professional help |
| Sewage/HVAC/major water damage | any area | specialized response |
| Recurring or hidden signs | area unknown | investigate moisture and extent |
Work through the project
Stop the water source
Address leakage, condensation, drainage, or another moisture driver before treating the visible symptom as complete.
Map visible patches
Measure and photograph accessible areas without destructive investigation that may spread contamination.
Apply every escalation check
Use EPA’s area branch together with water source, contamination, HVAC, health, and recurrence considerations.
Safety and scope
- People with health concerns should consult appropriate health guidance before cleanup.
- Sewage, extensive water damage, HVAC contamination, or unsafe building conditions are not ordinary surface-cleaning projects.
Sources and scope
Source links reviewed July 16, 2026. A review date is not the document's publication date.
- U.S. Environmental Protection Agency: Mold Cleanup in Your HomeUnited States · government guide
EPA uses an area of about 10 square feet as a decision point while also identifying other reasons to seek professional help.