diff --git a/databuilder/extractor/athena_metadata_extractor.py b/databuilder/extractor/athena_metadata_extractor.py
index 9ef75e31a..83785b044 100644
--- a/databuilder/extractor/athena_metadata_extractor.py
+++ b/databuilder/extractor/athena_metadata_extractor.py
@@ -63,6 +63,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableMetadata, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/druid_metadata_extractor.py b/databuilder/extractor/druid_metadata_extractor.py
index b2f7766ba..2d918cbb6 100644
--- a/databuilder/extractor/druid_metadata_extractor.py
+++ b/databuilder/extractor/druid_metadata_extractor.py
@@ -59,6 +59,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableMetadata, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/mssql_metadata_extractor.py b/databuilder/extractor/mssql_metadata_extractor.py
index ce89752a0..e19bf0eb1 100644
--- a/databuilder/extractor/mssql_metadata_extractor.py
+++ b/databuilder/extractor/mssql_metadata_extractor.py
@@ -116,6 +116,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableMetadata, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/presto_view_metadata_extractor.py b/databuilder/extractor/presto_view_metadata_extractor.py
index 0a3452774..e33bfe848 100644
--- a/databuilder/extractor/presto_view_metadata_extractor.py
+++ b/databuilder/extractor/presto_view_metadata_extractor.py
@@ -62,6 +62,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableMetadata, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/snowflake_metadata_extractor.py b/databuilder/extractor/snowflake_metadata_extractor.py
index 33f0eda3b..df1b2a414 100644
--- a/databuilder/extractor/snowflake_metadata_extractor.py
+++ b/databuilder/extractor/snowflake_metadata_extractor.py
@@ -106,6 +106,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableMetadata, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/snowflake_table_last_updated_extractor.py b/databuilder/extractor/snowflake_table_last_updated_extractor.py
index d477cece4..627095dca 100644
--- a/databuilder/extractor/snowflake_table_last_updated_extractor.py
+++ b/databuilder/extractor/snowflake_table_last_updated_extractor.py
@@ -83,6 +83,9 @@ def init(self, conf: ConfigTree) -> None:
         self._alchemy_extractor.init(sql_alch_conf)
         self._extract_iter: Union[None, Iterator] = None
 
+    def close(self) -> None:
+        self._alchemy_extractor.close()
+
     def extract(self) -> Union[TableLastUpdated, None]:
         if not self._extract_iter:
             self._extract_iter = self._get_extract_iter()
diff --git a/databuilder/extractor/sql_alchemy_extractor.py b/databuilder/extractor/sql_alchemy_extractor.py
index a375781a5..a8b64a134 100644
--- a/databuilder/extractor/sql_alchemy_extractor.py
+++ b/databuilder/extractor/sql_alchemy_extractor.py
@@ -38,6 +38,9 @@ def init(self, conf: ConfigTree) -> None:
             self.model_class = getattr(mod, class_name)
         self._execute_query()
 
+    def close(self) -> None:
+        self.connection.close()
+
     def _get_connection(self) -> Any:
         """
         Create a SQLAlchemy connection to Database