diff --git a/internal/pushrules/default_override.go b/internal/pushrules/default_override.go
index f97427b71..0f0484f0f 100644
--- a/internal/pushrules/default_override.go
+++ b/internal/pushrules/default_override.go
@@ -1,5 +1,9 @@
 package pushrules
 
+import (
+	"github.com/matrix-org/dendrite/roomserver/acls"
+)
+
 func defaultOverrideRules(userID string) []*Rule {
 	return []*Rule{
 		&mRuleMasterDefinition,
@@ -108,7 +112,7 @@ var (
 			{
 				Kind:    EventMatchCondition,
 				Key:     "type",
-				Pattern: pointer("m.room.server_acl"),
+				Pattern: pointer(acls.MRoomServerACL),
 			},
 			{
 				Kind:    EventMatchCondition,
diff --git a/roomserver/acls/acls.go b/roomserver/acls/acls.go
index b18daa3de..1b27ba639 100644
--- a/roomserver/acls/acls.go
+++ b/roomserver/acls/acls.go
@@ -27,6 +27,8 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+const MRoomServerACL = "m.room.server_acl"
+
 type ServerACLDatabase interface {
 	// GetKnownRooms returns a list of all rooms we know about.
 	GetKnownRooms(ctx context.Context) ([]string, error)
@@ -55,7 +57,7 @@ func NewServerACLs(db ServerACLDatabase) *ServerACLs {
 	// do then we'll process it into memory so that we have the regexes to
 	// hand.
 	for _, room := range rooms {
-		state, err := db.GetStateEvent(ctx, room, "m.room.server_acl", "")
+		state, err := db.GetStateEvent(ctx, room, MRoomServerACL, "")
 		if err != nil {
 			logrus.WithError(err).Errorf("Failed to get server ACLs for room %q", room)
 			continue
diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 23d8dc6c6..3d883158b 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -24,6 +24,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/matrix-org/dendrite/roomserver/acls"
 	"github.com/tidwall/gjson"
 
 	"github.com/matrix-org/gomatrixserverlib"
@@ -552,7 +553,7 @@ func (r *Inputer) processStateBefore(
 		// We also query the m.room.server_acl, if any, so we can correctly set
 		// them after joining a room.
 		tuplesNeeded = append(tuplesNeeded, gomatrixserverlib.StateKeyTuple{
-			EventType: "m.room.server_acl",
+			EventType: acls.MRoomServerACL,
 			StateKey:  "",
 		})
 		stateBeforeReq := &api.QueryStateAfterEventsRequest{
@@ -585,7 +586,7 @@ func (r *Inputer) processStateBefore(
 	// Work out what the history visibility/ACLs was at the time of the
 	// event.
 	for _, event := range stateBeforeEvent {
-		if event.Type() == "m.room.server_acl" && event.StateKeyEquals("") {
+		if input.Kind == api.KindNew && event.Type() == acls.MRoomServerACL && event.StateKeyEquals("") {
 			r.ACLs.OnServerACLUpdate(event)
 		}
 		if event.Type() != gomatrixserverlib.MRoomHistoryVisibility || !event.StateKeyEquals("") {
diff --git a/roomserver/producers/roomevent.go b/roomserver/producers/roomevent.go
index 9c4521986..a31fbb3cd 100644
--- a/roomserver/producers/roomevent.go
+++ b/roomserver/producers/roomevent.go
@@ -73,7 +73,7 @@ func (r *RoomEventProducer) ProduceRoomEvents(roomID string, updates []api.Outpu
 				}
 			}
 
-			if eventType == "m.room.server_acl" && update.NewRoomEvent.Event.StateKeyEquals("") {
+			if eventType == acls.MRoomServerACL && update.NewRoomEvent.Event.StateKeyEquals("") {
 				ev := update.NewRoomEvent.Event.Unwrap()
 				defer r.ACLs.OnServerACLUpdate(ev)
 			}
diff --git a/roomserver/roomserver_test.go b/roomserver/roomserver_test.go
index ab0bb188e..77b8deb51 100644
--- a/roomserver/roomserver_test.go
+++ b/roomserver/roomserver_test.go
@@ -577,7 +577,7 @@ func TestNewServerACLs(t *testing.T) {
 	alice := test.NewUser(t)
 	roomWithACL := test.NewRoom(t, alice)
 
-	roomWithACL.CreateAndInsert(t, alice, "m.room.server_acl", acls.ServerACL{
+	roomWithACL.CreateAndInsert(t, alice, acls.MRoomServerACL, acls.ServerACL{
 		Allowed:         []string{"*"},
 		Denied:          []string{"localhost"},
 		AllowIPLiterals: false,