diff --git a/Source/hydro/Castro_hybrid.cpp b/Source/hydro/Castro_hybrid.cpp
index b1bdabc4f9..5d52ea07f1 100644
--- a/Source/hydro/Castro_hybrid.cpp
+++ b/Source/hydro/Castro_hybrid.cpp
@@ -14,6 +14,10 @@ Castro::construct_old_hybrid_source(MultiFab& source, MultiFab& state_old, Real
 
     BL_PROFILE("Castro::construct_old_hybrid_source()");
 
+    if (! castro::hybrid_hydro) {
+        return;
+    }
+
     const Real strt_time = ParallelDescriptor::second();
 
     Real mult_factor = 1.0;
@@ -49,6 +53,10 @@ Castro::construct_new_hybrid_source(MultiFab& source, MultiFab& state_old, Multi
 
     BL_PROFILE("Castro::construct_new_hybrid_source()");
 
+    if (! castro::hybrid_hydro) {
+        return;
+    }
+
     const Real strt_time = ParallelDescriptor::second();
 
     // Start by subtracting off the old-time data.
diff --git a/Source/sources/Castro_sources.cpp b/Source/sources/Castro_sources.cpp
index 9a0be7b695..4581b74842 100644
--- a/Source/sources/Castro_sources.cpp
+++ b/Source/sources/Castro_sources.cpp
@@ -80,7 +80,11 @@ Castro::source_flag(int src)
 
 #ifdef HYBRID_MOMENTUM
     case hybrid_src:
-        return true;
+        if (castro::hybrid_hydro) {
+            return true;
+        } else {
+            return false;
+        }
 #endif
 
 #ifdef GRAVITY