diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 553561f..da05437 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -3,9 +3,12 @@ on:
   pull_request:
     branches:
       - master
+env:
+  BASE_REPO: ${{ github.event.pull_request.base.repo.clone_url }}
+  PR_HEAD_REPO: ${{ github.event.pull_request.head.repo.clone_url }}
 jobs:
   maven-verify:
-    if: github.repository_owner != 'entur'
+    if: ${{ env.BASE_REPO != env.PR_HEAD_REPO }}
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v4