Colonization begins within 24 to 48 hours once drywall reaches 20 percent moisture content

https://express-moisture-removal-cs.capitaljays.com/posts/your-insurance-may-cover-water-damage-filed-within-30-to-90-days-of-discovery

No, drywall should not get wet at all—even minor moisture exposure poses a serious mold risk. Documented research shows that mold colonization begins within 24 to 48 hours once drywall moisture content reaches 20 percent, well below saturation