diff --git a/changelog.d/3764.misc b/changelog.d/3764.misc
new file mode 100644
index 0000000000..f3614f1982
--- /dev/null
+++ b/changelog.d/3764.misc
@@ -0,0 +1 @@
+Make sure that we close db connections opened during init
\ No newline at end of file
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index 3348a8ec6d..86b5067400 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -51,10 +51,7 @@ class AppserviceSlaveStore(
 
 
 class AppserviceServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = AppserviceSlaveStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = AppserviceSlaveStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index ab79a45646..ce2b113dbb 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -74,10 +74,7 @@ class ClientReaderSlavedStore(
 
 
 class ClientReaderServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = ClientReaderSlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = ClientReaderSlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index a34c89fa99..f98e456ea0 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -90,10 +90,7 @@ class EventCreatorSlavedStore(
 
 
 class EventCreatorServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = EventCreatorSlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = EventCreatorSlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index 7d8105778d..60f5973505 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -72,10 +72,7 @@ class FederationReaderSlavedStore(
 
 
 class FederationReaderServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = FederationReaderSlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = FederationReaderSlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index d59007099b..60dd09aac3 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -78,10 +78,7 @@ class FederationSenderSlaveStore(
 
 
 class FederationSenderServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = FederationSenderSlaveStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = FederationSenderSlaveStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 8d484c1cd4..8c0b9c67b0 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -148,10 +148,7 @@ class FrontendProxySlavedStore(
 
 
 class FrontendProxyServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = FrontendProxySlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = FrontendProxySlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 005921dcf7..3eb5b663de 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -62,7 +62,7 @@ from synapse.rest.key.v1.server_key_resource import LocalKey
 from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.rest.media.v0.content_repository import ContentRepoResource
 from synapse.server import HomeServer
-from synapse.storage import are_all_users_on_domain
+from synapse.storage import DataStore, are_all_users_on_domain
 from synapse.storage.engines import IncorrectDatabaseSetup, create_engine
 from synapse.storage.prepare_database import UpgradeDatabaseException, prepare_database
 from synapse.util.caches import CACHE_SIZE_FACTOR
@@ -111,6 +111,8 @@ def build_resource_for_web_client(hs):
 
 
 class SynapseHomeServer(HomeServer):
+    DATASTORE_CLASS = DataStore
+
     def _listener_http(self, config, listener_config):
         port = listener_config["port"]
         bind_addresses = listener_config["bind_addresses"]
@@ -356,13 +358,13 @@ def setup(config_options):
     logger.info("Preparing database: %s...", config.database_config['name'])
 
     try:
-        db_conn = hs.get_db_conn(run_new_connection=False)
-        prepare_database(db_conn, database_engine, config=config)
-        database_engine.on_new_connection(db_conn)
+        with hs.get_db_conn(run_new_connection=False) as db_conn:
+            prepare_database(db_conn, database_engine, config=config)
+            database_engine.on_new_connection(db_conn)
 
-        hs.run_startup_checks(db_conn, database_engine)
+            hs.run_startup_checks(db_conn, database_engine)
 
-        db_conn.commit()
+            db_conn.commit()
     except UpgradeDatabaseException:
         sys.stderr.write(
             "\nFailed to upgrade database.\n"
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index fd1f6cbf7e..e3dbb3b4e6 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -60,10 +60,7 @@ class MediaRepositorySlavedStore(
 
 
 class MediaRepositoryServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = MediaRepositorySlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = MediaRepositorySlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index a4fc7e91fa..244c604de9 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -78,10 +78,7 @@ class PusherSlaveStore(
 
 
 class PusherServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = PusherSlaveStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = PusherSlaveStore
 
     def remove_pusher(self, app_id, push_key, user_id):
         self.get_tcp_replication().send_remove_pusher(app_id, push_key, user_id)
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index 27e1998660..6662340797 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -249,10 +249,7 @@ class SynchrotronApplicationService(object):
 
 
 class SynchrotronServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = SynchrotronSlavedStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = SynchrotronSlavedStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index 1388a42b59..96ffcaf073 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -94,10 +94,7 @@ class UserDirectorySlaveStore(
 
 
 class UserDirectoryServer(HomeServer):
-    def setup(self):
-        logger.info("Setting up.")
-        self.datastore = UserDirectorySlaveStore(self.get_db_conn(), self)
-        logger.info("Finished setting up.")
+    DATASTORE_CLASS = UserDirectorySlaveStore
 
     def _listen_http(self, listener_config):
         port = listener_config["port"]
diff --git a/synapse/server.py b/synapse/server.py
index a6fbc6ec0c..938a05f9dc 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -19,6 +19,7 @@
 # partial one for unit test mocking.
 
 # Imports required for the default HomeServer() implementation
+import abc
 import logging
 
 from twisted.enterprise import adbapi
@@ -81,7 +82,6 @@ from synapse.server_notices.server_notices_manager import ServerNoticesManager
 from synapse.server_notices.server_notices_sender import ServerNoticesSender
 from synapse.server_notices.worker_server_notices_sender import WorkerServerNoticesSender
 from synapse.state import StateHandler, StateResolutionHandler
-from synapse.storage import DataStore
 from synapse.streams.events import EventSources
 from synapse.util import Clock
 from synapse.util.distributor import Distributor
@@ -111,6 +111,8 @@ class HomeServer(object):
         config (synapse.config.homeserver.HomeserverConfig):
     """
 
+    __metaclass__ = abc.ABCMeta
+
     DEPENDENCIES = [
         'http_client',
         'db_pool',
@@ -172,6 +174,11 @@ class HomeServer(object):
         'room_context_handler',
     ]
 
+    # This is overridden in derived application classes
+    # (such as synapse.app.homeserver.SynapseHomeServer) and gives the class to be
+    # instantiated during setup() for future return by get_datastore()
+    DATASTORE_CLASS = abc.abstractproperty()
+
     def __init__(self, hostname, reactor=None, **kwargs):
         """
         Args:
@@ -188,13 +195,16 @@ class HomeServer(object):
         self.distributor = Distributor()
         self.ratelimiter = Ratelimiter()
 
+        self.datastore = None
+
         # Other kwargs are explicit dependencies
         for depname in kwargs:
             setattr(self, depname, kwargs[depname])
 
     def setup(self):
         logger.info("Setting up.")
-        self.datastore = DataStore(self.get_db_conn(), self)
+        with self.get_db_conn() as conn:
+            self.datastore = self.DATASTORE_CLASS(conn, self)
         logger.info("Finished setting up.")
 
     def get_reactor(self):
diff --git a/tests/storage/test_base.py b/tests/storage/test_base.py
index 7cb5f0e4cf..829f47d2e8 100644
--- a/tests/storage/test_base.py
+++ b/tests/storage/test_base.py
@@ -20,11 +20,11 @@ from mock import Mock
 
 from twisted.internet import defer
 
-from synapse.server import HomeServer
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.engines import create_engine
 
 from tests import unittest
+from tests.utils import TestHomeServer
 
 
 class SQLBaseStoreTestCase(unittest.TestCase):
@@ -51,7 +51,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         config = Mock()
         config.event_cache_size = 1
         config.database_config = {"name": "sqlite3"}
-        hs = HomeServer(
+        hs = TestHomeServer(
             "test",
             db_pool=self.db_pool,
             config=config,
diff --git a/tests/test_types.py b/tests/test_types.py
index be072d402b..0f5c8bfaf9 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 from synapse.api.errors import SynapseError
-from synapse.server import HomeServer
 from synapse.types import GroupID, RoomAlias, UserID
 
 from tests import unittest
+from tests.utils import TestHomeServer
 
-mock_homeserver = HomeServer(hostname="my.domain")
+mock_homeserver = TestHomeServer(hostname="my.domain")
 
 
 class UserIDTestCase(unittest.TestCase):
diff --git a/tests/utils.py b/tests/utils.py
index e8ef10445c..657c258a6e 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -29,7 +29,7 @@ from synapse.api.errors import CodeMessageException, cs_error
 from synapse.federation.transport import server
 from synapse.http.server import HttpServer
 from synapse.server import HomeServer
-from synapse.storage import PostgresEngine
+from synapse.storage import DataStore, PostgresEngine
 from synapse.storage.engines import create_engine
 from synapse.storage.prepare_database import (
     _get_or_create_schema_state,
@@ -92,10 +92,14 @@ def setupdb():
         atexit.register(_cleanup)
 
 
+class TestHomeServer(HomeServer):
+    DATASTORE_CLASS = DataStore
+
+
 @defer.inlineCallbacks
 def setup_test_homeserver(
     cleanup_func, name="test", datastore=None, config=None, reactor=None,
-    homeserverToUse=HomeServer, **kargs
+    homeserverToUse=TestHomeServer, **kargs
 ):
     """
     Setup a homeserver suitable for running tests against.  Keyword arguments