diff --git a/alfalfa_worker/lib/utils.py b/alfalfa_worker/lib/utils.py
index 82c5f492..e20f5553 100644
--- a/alfalfa_worker/lib/utils.py
+++ b/alfalfa_worker/lib/utils.py
@@ -24,9 +24,11 @@ def to_bool(value: str):
     true_strings = ["true", "yes", "1"]
     if isinstance(value, bool):
         return value
-    elif value.lower() in false_strings:
+    if value is None:
         return False
-    elif value.lower() in true_strings:
-        return True
-    else:
-        raise ValueError(f"Invalid string \"{value}\" provided for boolean conversion")
+    if isinstance(value, str):
+        if value.lower() in false_strings:
+            return False
+        elif value.lower() in true_strings:
+            return True
+    raise ValueError(f"Invalid string \"{value}\" provided for boolean conversion")
diff --git a/tests/worker/test_job_step_run.py b/tests/worker/test_job_step_run.py
index 29999a6a..9ce8b1e1 100644
--- a/tests/worker/test_job_step_run.py
+++ b/tests/worker/test_job_step_run.py
@@ -26,7 +26,7 @@ def step_run_mock_job(dispatcher: Dispatcher):
         "start_datetime": str(datetime(2019, 1, 2, 0, 0, 0)),
         "end_datetime": str(datetime(2019, 1, 3, 0, 0, 0)),
         "timescale": "20",
-        "realtime": None
+        "realtime": False
     }
 
     yield dispatcher.create_job(StepRunMockJob.job_path(), params)