diff --git a/tap_postgres/tap.py b/tap_postgres/tap.py
index 6c2c81a4..4dea1188 100644
--- a/tap_postgres/tap.py
+++ b/tap_postgres/tap.py
@@ -396,10 +396,13 @@ def get_sqlalchemy_query(self, config: Mapping[str, Any]) -> dict:
         if config["ssl_enable"]:
             ssl_mode = config["ssl_mode"]
             query.update({"sslmode": ssl_mode})
-            query["sslrootcert"] = self.filepath_or_certificate(
-                value=config["ssl_certificate_authority"],
-                alternative_name=config["ssl_storage_directory"] + "/root.crt",
-            )
+            if ssl_mode in ("verify-ca", "verify-full") and config.get(
+                "ssl_certificate_authority"
+            ):
+                query["sslrootcert"] = self.filepath_or_certificate(
+                    value=config["ssl_certificate_authority"],
+                    alternative_name=config["ssl_storage_directory"] + "/root.crt",
+                )
 
         # ssl_client_certificate_enable is for verifying the client's identity to the
         # server.