Can a Pennsylvania tenant file a counter-claim during eviction?

Yes, in most Pennsylvania jurisdictions. A tenant facing eviction can raise affirmative defenses (improper notice, retaliation, breach of warranty of habitability) and counter-claims (overcharged rent, withheld deposit, harassment damages). The counter-claim is heard with the eviction in the same proceeding. Tenant counter-claims for habitability defects often reduce the rent owed (rent abatement) and can sometimes wipe out the eviction entirely if the unit was uninhabitable. Common tenant evidence: photos of defects, written maintenance requests, code enforcement violations, witness testimony from a neighbor or guest. The landlord should expect a counter-claim if any habitability or repair issue is documented in the file. The cleanest landlord case has documented prompt repair responses to all written tenant complaints.

Source: Pennsylvania unlawful detainer procedure; counter-claim rules