Determining when the applicable statute of limitations begins to run can be one of the most divisive and contested issues in a lawsuit. One doctrine that can equitably toll the running of a statute of limitations and is applied with relative frequency is the discovery rule.

The discovery rule permits a plaintiff to file its claims even after the statute of limitations has expired, provided that the plaintiff was reasonably unaware, despite due diligence, that the plaintiff’s injuries were caused by another’s wrongdoing, see Gleason v. Borough of Moosic, 15 A.3d 479, 484 (Pa. 2011); see also, Fine v. Checcio, 870 A.2d 850 (Pa. 2005). The discovery rule balances forcing defendants to defend against stale claims with offering diligent plaintiffs an opportunity to recover for their injuries. See Gleason, 15 A.3d at 484–85; Pocono International Raceway v. Pocono Produce, 468 A.2d 468, 471 (Pa. 1983); and, Carlino v. Ethicon, 208 A.3d 92, 104 (Pa. Super Ct. 2019).

When Does the Discovery Rule Apply?