diff --git a/Makefile.am b/Makefile.am
index 2daf76f..edbebfa 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -56,7 +56,7 @@
 	$(PHOSPHOR_LOGGING_CFLAGS) \
 	$(CODE_COVERAGE_CXXFLAGS)
 
-swampd_SOURCES = main.cpp util.cpp
+swampd_SOURCES = main.cpp
 swampd_LDADD = \
 	$(SDBUSPLUS_LIBS) \
 	libswampd.la
@@ -94,6 +94,7 @@
 	sensors/builder.cpp \
 	sensors/buildjson.cpp \
 	sensors/manager.cpp \
+	sensors/build_utils.cpp \
 	pid/ec/pid.cpp \
 	pid/ec/stepwise.cpp \
 	pid/fancontroller.cpp \
diff --git a/util.cpp b/sensors/build_utils.cpp
similarity index 94%
rename from util.cpp
rename to sensors/build_utils.cpp
index ec60d7a..c3c7ce1 100644
--- a/util.cpp
+++ b/sensors/build_utils.cpp
@@ -14,9 +14,10 @@
  * limitations under the License.
  */
 
-#include "util.hpp"
+#include "build_utils.hpp"
 
-#include <string>
+namespace pid_control
+{
 
 static constexpr auto external_sensor =
     "/xyz/openbmc_project/extsensors/";                         // type/
@@ -68,3 +69,5 @@
 
     return IOInterfaceType::UNKNOWN;
 }
+
+} // namespace pid_control
diff --git a/sensors/build_utils.hpp b/sensors/build_utils.hpp
new file mode 100644
index 0000000..bb2b41c
--- /dev/null
+++ b/sensors/build_utils.hpp
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+
+namespace pid_control
+{
+
+/* This program assumes sensors use the Sensor.Value interface
+ * and for sensor->write() I only implemented sysfs as a type,
+ * but -- how would it know whether to use Control.FanSpeed or Control.FanPwm?
+ *
+ * One could get the interface list for the object and search for Control.*
+ * but, it needs to know the maximum, minimum.  The only sensors it wants to
+ * write in this code base are Fans...
+ */
+enum class IOInterfaceType
+{
+    NONE, // There is no interface.
+    EXTERNAL,
+    DBUSPASSIVE,
+    DBUSACTIVE, // This means for write that it needs to look up the interface.
+    SYSFS,
+    UNKNOWN
+};
+
+/* WriteInterfaceType is different because Dbusactive/passive. how to know... */
+IOInterfaceType getWriteInterfaceType(const std::string& path);
+
+IOInterfaceType getReadInterfaceType(const std::string& path);
+
+} // namespace pid_control
diff --git a/sensors/builder.cpp b/sensors/builder.cpp
index 4da1cf2..1cea61a 100644
--- a/sensors/builder.cpp
+++ b/sensors/builder.cpp
@@ -26,6 +26,7 @@
 #include "interfaces.hpp"
 #include "notimpl/readonly.hpp"
 #include "notimpl/writeonly.hpp"
+#include "sensors/build_utils.hpp"
 #include "sensors/builder.hpp"
 #include "sensors/host.hpp"
 #include "sensors/manager.hpp"
@@ -37,6 +38,10 @@
 static constexpr bool deferSignals = true;
 static DbusHelper helper;
 
+using ::pid_control::getReadInterfaceType;
+using ::pid_control::getWriteInterfaceType;
+using ::pid_control::IOInterfaceType;
+
 SensorManager
     buildSensors(const std::map<std::string, struct conf::SensorConfig>& config,
                  sdbusplus::bus::bus& passive, sdbusplus::bus::bus& host)
diff --git a/test/Makefile.am b/test/Makefile.am
index 3d74c88..0703f73 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -40,7 +40,7 @@
 sensor_host_unittest_LDADD = $(top_builddir)/sensors/host.o
 
 util_unittest_SOURCES = util_unittest.cpp
-util_unittest_LDADD = $(top_builddir)/util.o
+util_unittest_LDADD = $(top_builddir)/sensors/build_utils.o
 
 pid_zone_unittest_SOURCES = pid_zone_unittest.cpp
 pid_zone_unittest_LDADD = $(top_builddir)/pid/ec/pid.o \
diff --git a/test/util_unittest.cpp b/test/util_unittest.cpp
index 6e5e548..457c470 100644
--- a/test/util_unittest.cpp
+++ b/test/util_unittest.cpp
@@ -1,10 +1,15 @@
-#include "util.hpp"
+#include "sensors/build_utils.hpp"
 
 #include <string>
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+namespace pid_control
+{
+namespace
+{
+
 TEST(UtilTest, WriteTypeEmptyString_ReturnsNONE)
 {
     // Verify it responds to an empty string.
@@ -80,3 +85,6 @@
     std::string path = "asdf09as0df9a0fd";
     EXPECT_EQ(IOInterfaceType::UNKNOWN, getReadInterfaceType(path));
 }
+
+} // namespace
+} // namespace pid_control
diff --git a/util.hpp b/util.hpp
index 4a2c2c3..7930dba 100644
--- a/util.hpp
+++ b/util.hpp
@@ -8,29 +8,6 @@
 #include <limits>
 #include <string>
 
-/* This program assumes sensors use the Sensor.Value interface
- * and for sensor->write() I only implemented sysfs as a type,
- * but -- how would it know whether to use Control.FanSpeed or Control.FanPwm?
- *
- * One could get the interface list for the object and search for Control.*
- * but, it needs to know the maximum, minimum.  The only sensors it wants to
- * write in this code base are Fans...
- */
-enum class IOInterfaceType
-{
-    NONE, // There is no interface.
-    EXTERNAL,
-    DBUSPASSIVE,
-    DBUSACTIVE, // This means for write that it needs to look up the interface.
-    SYSFS,
-    UNKNOWN
-};
-
-/* WriteInterfaceType is different because Dbusactive/passive. how to know... */
-IOInterfaceType getWriteInterfaceType(const std::string& path);
-
-IOInterfaceType getReadInterfaceType(const std::string& path);
-
 void tryRestartControlLoops(void);
 
 /*