diff --git a/src/core/lib/support/log.c b/src/core/lib/support/log.c
index bae0957df72097d584d42ff593786d7b29d1f14b..899f1218b60b77c19089afd99c5f214d3d0b289f 100644
--- a/src/core/lib/support/log.c
+++ b/src/core/lib/support/log.c
@@ -79,17 +79,18 @@ void gpr_set_log_verbosity(gpr_log_severity min_severity_to_print) {
 
 void gpr_log_verbosity_init() {
   char *verbosity = gpr_getenv("GRPC_VERBOSITY");
-  if (verbosity == NULL) return;
 
-  gpr_atm min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
-  if (strcmp(verbosity, "DEBUG") == 0) {
-    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_DEBUG;
-  } else if (strcmp(verbosity, "INFO") == 0) {
-    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_INFO;
-  } else if (strcmp(verbosity, "ERROR") == 0) {
-    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_ERROR;
+  gpr_atm min_severity_to_print = GPR_LOG_SEVERITY_ERROR;
+  if (verbosity != NULL) {
+    if (strcmp(verbosity, "DEBUG") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_DEBUG;
+    } else if (strcmp(verbosity, "INFO") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_INFO;
+    } else if (strcmp(verbosity, "ERROR") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_ERROR;
+    }
+    gpr_free(verbosity);
   }
-  gpr_free(verbosity);
   if ((gpr_atm_no_barrier_load(&g_min_severity_to_print)) ==
       GPR_LOG_VERBOSITY_UNSET) {
     gpr_atm_no_barrier_store(&g_min_severity_to_print, min_severity_to_print);
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 7dd9e12614655b184a2bd9b49c16387395392e3f..d5f28fce6b51ea0ec1ea38f6903faad87e8675ab 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -61,7 +61,9 @@ _ROOT = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '../..'))
 os.chdir(_ROOT)
 
 
-_FORCE_ENVIRON_FOR_WRAPPERS = {}
+_FORCE_ENVIRON_FOR_WRAPPERS = {
+  'GRPC_VERBOSITY': 'DEBUG',
+}
 
 
 _POLLING_STRATEGIES = {
@@ -162,7 +164,8 @@ class CLanguage(object):
       for polling_strategy in polling_strategies:
         env={'GRPC_DEFAULT_SSL_ROOTS_FILE_PATH':
                  _ROOT + '/src/core/lib/tsi/test_creds/ca.pem',
-             'GRPC_POLL_STRATEGY': polling_strategy}
+             'GRPC_POLL_STRATEGY': polling_strategy,
+             'GRPC_VERBOSITY': 'DEBUG'}
         shortname_ext = '' if polling_strategy=='all' else ' GRPC_POLL_STRATEGY=%s' % polling_strategy
         if self.config.build_config in target['exclude_configs']:
           continue