diff --git a/.github/workflows/test-warehouse.yml b/.github/workflows/test-warehouse.yml
index b90c243be..1ae051426 100644
--- a/.github/workflows/test-warehouse.yml
+++ b/.github/workflows/test-warehouse.yml
@@ -183,7 +183,15 @@ jobs:
           curl -fsSL https://public.cdn.getdbt.com/fs/install/install.sh | sh -s --
 
       - name: Install Elementary
-        run: pip install "./elementary[${{ (inputs.warehouse-type == 'databricks_catalog' && 'databricks') || inputs.warehouse-type }}]"
+        run: |
+          # For Vertica, dbt-vertica is already installed with --no-deps above;
+          # using ".[vertica]" would re-resolve dbt-vertica's deps and downgrade
+          # dbt-core to ~=1.8.  Install elementary without the adapter extra.
+          if [ "${{ inputs.warehouse-type }}" = "vertica" ]; then
+            pip install "./elementary"
+          else
+            pip install "./elementary[${{ (inputs.warehouse-type == 'databricks_catalog' && 'databricks') || inputs.warehouse-type }}]"
+          fi
 
       - name: Write dbt profiles
         env: