diff --git a/pkg/cluster/cluster.go b/pkg/cluster/cluster.go
index 9937deff3..17e8c6747 100644
--- a/pkg/cluster/cluster.go
+++ b/pkg/cluster/cluster.go
@@ -41,7 +41,7 @@ import (
 var (
 	alphaNumericRegexp    = regexp.MustCompile("^[a-zA-Z][a-zA-Z0-9]*$")
 	databaseNameRegexp    = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
-	userRegexp            = regexp.MustCompile(`^[a-z0-9]([-_a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-_a-z0-9]*[a-z0-9])?)*$`)
+	userRegexp            = regexp.MustCompile(`^[a-z0-9,]+\.?[-_a-z0-9,]+[a-z0-9,]$`)
 	patroniObjectSuffixes = []string{"config", "failover", "sync"}
 )
 
@@ -1093,16 +1093,12 @@ func (c *Cluster) initRobotUsers() error {
 		if c.shouldAvoidProtectedOrSystemRole(username, "manifest robot role") {
 			continue
 		}
-		name := username
 		namespace := c.Namespace
 
+		//more than one dot in the username is reported invalid by regexp
 		if strings.Contains(username, ".") {
 			splits := strings.Split(username, ".")
-			name = splits[1]
-			if len(splits[0]) > 0 {
-				namespace = splits[0]
-			}
-			username = name
+			namespace = splits[0]
 		}
 
 		flags, err := normalizeUserFlags(userFlags)
@@ -1115,18 +1111,14 @@ func (c *Cluster) initRobotUsers() error {
 		}
 		newRole := spec.PgUser{
 			Origin:    spec.RoleOriginManifest,
-			Name:      name,
+			Name:      username,
 			Namespace: namespace,
 			Password:  util.RandomPassword(constants.PasswordLength),
 			Flags:     flags,
 			AdminRole: adminRole,
 		}
 		if currentRole, present := c.pgUsers[username]; present {
-			if namespace == c.pgUsers[username].Namespace {
-				c.pgUsers[username] = c.resolveNameConflict(&currentRole, &newRole)
-			} else {
-				c.pgUsers[username+"."+namespace] = newRole
-			}
+			c.pgUsers[username] = c.resolveNameConflict(&currentRole, &newRole)
 		} else {
 			c.pgUsers[username] = newRole
 		}
diff --git a/pkg/cluster/cluster_test.go b/pkg/cluster/cluster_test.go
index 7ccad19f1..df46a38f3 100644
--- a/pkg/cluster/cluster_test.go
+++ b/pkg/cluster/cluster_test.go
@@ -902,7 +902,7 @@ func TestCrossNamespacedSecrets(t *testing.T) {
 
 	userNamespaceMap := map[string]string{
 		cluster.Namespace: "db_user",
-		"appspace":        "db_user",
+		"appspace":        "appspace.db_user",
 	}
 
 	err := cluster.initRobotUsers()
@@ -912,7 +912,19 @@ func TestCrossNamespacedSecrets(t *testing.T) {
 
 	for _, u := range cluster.pgUsers {
 		if u.Name != userNamespaceMap[u.Namespace] {
-			t.Errorf("%s: Could not create namespaced user in its correct namespaces", testName)
+			t.Errorf("%s: Could not create namespaced user in its correct namespaces for user %s in namespace %s", testName, u.Name, u.Namespace)
+		}
+	}
+}
+
+func TestValidUsernames(t *testing.T) {
+	testName := "test username validity"
+
+	invalidUsernames := []string{"_", ".", ".user", "appspace.", "appspace.user.extra", "user_", "_user", "-user", "user-"}
+
+	for _, username := range invalidUsernames {
+		if isValidUsername(username) {
+			t.Errorf("%s Invalid username is allowed: %s", testName, username)
 		}
 	}
 }
diff --git a/pkg/cluster/k8sres.go b/pkg/cluster/k8sres.go
index af01bd1b9..98f64449b 100644
--- a/pkg/cluster/k8sres.go
+++ b/pkg/cluster/k8sres.go
@@ -1581,13 +1581,10 @@ func (c *Cluster) generateSingleUserSecret(namespace string, pgUser spec.PgUser)
 	if username == constants.ConnectionPoolerUserName {
 		lbls = c.connectionPoolerLabels("", false).MatchLabels
 	}
-	secret_name := username
-	if pgUser.Namespace != c.Namespace {
-		secret_name = username + "." + pgUser.Namespace
-	}
+
 	secret := v1.Secret{
 		ObjectMeta: metav1.ObjectMeta{
-			Name:        c.credentialSecretName(secret_name),
+			Name:        c.credentialSecretName(username),
 			Namespace:   pgUser.Namespace,
 			Labels:      lbls,
 			Annotations: c.annotationsSet(nil),
diff --git a/pkg/cluster/sync.go b/pkg/cluster/sync.go
index 112a0cf1f..43e56d14c 100644
--- a/pkg/cluster/sync.go
+++ b/pkg/cluster/sync.go
@@ -552,11 +552,13 @@ func (c *Cluster) syncRoles() (err error) {
 	}()
 
 	for _, u := range c.pgUsers {
+		pg_role := u.Name
 		if u.Namespace != c.Namespace {
-			userNames = append(userNames, u.Name+"."+"u.Namespace")
-		} else {
-			userNames = append(userNames, u.Name)
+			// to avoid the conflict of having multiple users of same name
+			// but each in different namespace.
+			pg_role = fmt.Sprintf("%s.%s", u.Name, u.Namespace)
 		}
+		userNames = append(userNames, pg_role)
 	}
 
 	if needMasterConnectionPooler(&c.Spec) || needReplicaConnectionPooler(&c.Spec) {