diff --git a/cmd/admin.go b/cmd/admin.go
index 858498ed37..27089a17c4 100644
--- a/cmd/admin.go
+++ b/cmd/admin.go
@@ -26,6 +26,7 @@ import (
 	auth_service "code.gitea.io/gitea/services/auth"
 	"code.gitea.io/gitea/services/auth/source/oauth2"
 	repo_service "code.gitea.io/gitea/services/repository"
+	user_service "code.gitea.io/gitea/services/user"
 
 	"github.com/urfave/cli"
 )
@@ -534,7 +535,7 @@ func runDeleteUser(c *cli.Context) error {
 		return fmt.Errorf("The user %s does not match the provided id %d", user.Name, c.Int64("id"))
 	}
 
-	return models.DeleteUser(user)
+	return user_service.DeleteUser(user)
 }
 
 func runRepoSyncReleases(_ *cli.Context) error {
diff --git a/models/admin/notice.go b/models/admin/notice.go
index c41e49ed8c..2d71b426dd 100644
--- a/models/admin/notice.go
+++ b/models/admin/notice.go
@@ -43,12 +43,7 @@ func (n *Notice) TrStr() string {
 }
 
 // CreateNotice creates new system notice.
-func CreateNotice(tp NoticeType, desc string, args ...interface{}) error {
-	return CreateNoticeCtx(db.DefaultContext, tp, desc, args...)
-}
-
-// CreateNoticeCtx creates new system notice.
-func CreateNoticeCtx(ctx context.Context, tp NoticeType, desc string, args ...interface{}) error {
+func CreateNotice(ctx context.Context, tp NoticeType, desc string, args ...interface{}) error {
 	if len(args) > 0 {
 		desc = fmt.Sprintf(desc, args...)
 	}
@@ -61,38 +56,28 @@ func CreateNoticeCtx(ctx context.Context, tp NoticeType, desc string, args ...in
 
 // CreateRepositoryNotice creates new system notice with type NoticeRepository.
 func CreateRepositoryNotice(desc string, args ...interface{}) error {
-	return CreateNoticeCtx(db.DefaultContext, NoticeRepository, desc, args...)
+	return CreateNotice(db.DefaultContext, NoticeRepository, desc, args...)
 }
 
 // RemoveAllWithNotice removes all directories in given path and
 // creates a system notice when error occurs.
-func RemoveAllWithNotice(title, path string) {
-	RemoveAllWithNoticeCtx(db.DefaultContext, title, path)
-}
-
-// RemoveStorageWithNotice removes a file from the storage and
-// creates a system notice when error occurs.
-func RemoveStorageWithNotice(bucket storage.ObjectStorage, title, path string) {
-	removeStorageWithNotice(db.DefaultContext, bucket, title, path)
-}
-
-func removeStorageWithNotice(ctx context.Context, bucket storage.ObjectStorage, title, path string) {
-	if err := bucket.Delete(path); err != nil {
+func RemoveAllWithNotice(ctx context.Context, title, path string) {
+	if err := util.RemoveAll(path); err != nil {
 		desc := fmt.Sprintf("%s [%s]: %v", title, path, err)
 		log.Warn(title+" [%s]: %v", path, err)
-		if err = CreateNoticeCtx(ctx, NoticeRepository, desc); err != nil {
+		if err = CreateNotice(ctx, NoticeRepository, desc); err != nil {
 			log.Error("CreateRepositoryNotice: %v", err)
 		}
 	}
 }
 
-// RemoveAllWithNoticeCtx removes all directories in given path and
+// RemoveStorageWithNotice removes a file from the storage and
 // creates a system notice when error occurs.
-func RemoveAllWithNoticeCtx(ctx context.Context, title, path string) {
-	if err := util.RemoveAll(path); err != nil {
+func RemoveStorageWithNotice(ctx context.Context, bucket storage.ObjectStorage, title, path string) {
+	if err := bucket.Delete(path); err != nil {
 		desc := fmt.Sprintf("%s [%s]: %v", title, path, err)
 		log.Warn(title+" [%s]: %v", path, err)
-		if err = CreateNoticeCtx(ctx, NoticeRepository, desc); err != nil {
+		if err = CreateNotice(ctx, NoticeRepository, desc); err != nil {
 			log.Error("CreateRepositoryNotice: %v", err)
 		}
 	}
diff --git a/models/admin/notice_test.go b/models/admin/notice_test.go
index 7272df4368..b4613db8e7 100644
--- a/models/admin/notice_test.go
+++ b/models/admin/notice_test.go
@@ -7,6 +7,7 @@ package admin
 import (
 	"testing"
 
+	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/unittest"
 
 	"github.com/stretchr/testify/assert"
@@ -28,7 +29,7 @@ func TestCreateNotice(t *testing.T) {
 		Description: "test description",
 	}
 	unittest.AssertNotExistsBean(t, noticeBean)
-	assert.NoError(t, CreateNotice(noticeBean.Type, noticeBean.Description))
+	assert.NoError(t, CreateNotice(db.DefaultContext, noticeBean.Type, noticeBean.Description))
 	unittest.AssertExistsAndLoadBean(t, noticeBean)
 }
 
diff --git a/models/consistency.go b/models/consistency.go
index 83cfbd0e49..ba669628b9 100644
--- a/models/consistency.go
+++ b/models/consistency.go
@@ -128,7 +128,7 @@ func DeleteOrphanedIssues() error {
 
 	// Remove issue attachment files.
 	for i := range attachmentPaths {
-		admin_model.RemoveAllWithNoticeCtx(db.DefaultContext, "Delete issue attachment", attachmentPaths[i])
+		admin_model.RemoveAllWithNotice(db.DefaultContext, "Delete issue attachment", attachmentPaths[i])
 	}
 	return nil
 }
diff --git a/models/org.go b/models/org.go
index 1840cae9fa..e0b4d27245 100644
--- a/models/org.go
+++ b/models/org.go
@@ -6,6 +6,7 @@
 package models
 
 import (
+	"context"
 	"fmt"
 	"strings"
 
@@ -14,9 +15,7 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
-	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/structs"
-	"code.gitea.io/gitea/modules/util"
 
 	"xorm.io/builder"
 	"xorm.io/xorm"
@@ -254,68 +253,23 @@ func CountOrganizations() int64 {
 	return count
 }
 
-// DeleteOrganization completely and permanently deletes everything of organization.
-func DeleteOrganization(org *User) (err error) {
-	if !org.IsOrganization() {
-		return fmt.Errorf("%s is a user not an organization", org.Name)
-	}
-
-	sess := db.NewSession(db.DefaultContext)
-	defer sess.Close()
-
-	if err = sess.Begin(); err != nil {
-		return err
-	}
-
-	if err = deleteOrg(sess, org); err != nil {
-		if IsErrUserOwnRepos(err) {
-			return err
-		} else if err != nil {
-			return fmt.Errorf("deleteOrg: %v", err)
-		}
-	}
-
-	return sess.Commit()
-}
-
-func deleteOrg(e *xorm.Session, u *User) error {
-	// Check ownership of repository.
-	count, err := getRepositoryCount(e, u)
-	if err != nil {
-		return fmt.Errorf("GetRepositoryCount: %v", err)
-	} else if count > 0 {
-		return ErrUserOwnRepos{UID: u.ID}
-	}
+// DeleteOrganization deletes models associated to an organization.
+func DeleteOrganization(ctx context.Context, org *User) error {
+	e := db.GetEngine(ctx)
 
 	if err := deleteBeans(e,
-		&Team{OrgID: u.ID},
-		&OrgUser{OrgID: u.ID},
-		&TeamUser{OrgID: u.ID},
-		&TeamUnit{OrgID: u.ID},
+		&Team{OrgID: org.ID},
+		&OrgUser{OrgID: org.ID},
+		&TeamUser{OrgID: org.ID},
+		&TeamUnit{OrgID: org.ID},
 	); err != nil {
 		return fmt.Errorf("deleteBeans: %v", err)
 	}
 
-	if _, err = e.ID(u.ID).Delete(new(User)); err != nil {
+	if _, err := e.ID(org.ID).Delete(new(User)); err != nil {
 		return fmt.Errorf("Delete: %v", err)
 	}
 
-	// FIXME: system notice
-	// Note: There are something just cannot be roll back,
-	//	so just keep error logs of those operations.
-	path := UserPath(u.Name)
-
-	if err := util.RemoveAll(path); err != nil {
-		return fmt.Errorf("Failed to RemoveAll %s: %v", path, err)
-	}
-
-	if len(u.Avatar) > 0 {
-		avatarPath := u.CustomAvatarRelativePath()
-		if err := storage.Avatars.Delete(avatarPath); err != nil {
-			return fmt.Errorf("Failed to remove %s: %v", avatarPath, err)
-		}
-	}
-
 	return nil
 }
 
diff --git a/models/org_test.go b/models/org_test.go
index 2bc4d74fc3..8580702a06 100644
--- a/models/org_test.go
+++ b/models/org_test.go
@@ -261,24 +261,6 @@ func TestCountOrganizations(t *testing.T) {
 	assert.Equal(t, expected, CountOrganizations())
 }
 
-func TestDeleteOrganization(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-	org := unittest.AssertExistsAndLoadBean(t, &User{ID: 6}).(*User)
-	assert.NoError(t, DeleteOrganization(org))
-	unittest.AssertNotExistsBean(t, &User{ID: 6})
-	unittest.AssertNotExistsBean(t, &OrgUser{OrgID: 6})
-	unittest.AssertNotExistsBean(t, &Team{OrgID: 6})
-
-	org = unittest.AssertExistsAndLoadBean(t, &User{ID: 3}).(*User)
-	err := DeleteOrganization(org)
-	assert.Error(t, err)
-	assert.True(t, IsErrUserOwnRepos(err))
-
-	user := unittest.AssertExistsAndLoadBean(t, &User{ID: 5}).(*User)
-	assert.Error(t, DeleteOrganization(user))
-	unittest.CheckConsistencyFor(t, &User{}, &Team{})
-}
-
 func TestIsOrganizationOwner(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	test := func(orgID, userID int64, expected bool) {
diff --git a/models/repo.go b/models/repo.go
index 57806a86f7..d62b3ec2b4 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -134,7 +134,7 @@ func NewRepoContext() {
 	loadRepoConfig()
 	unit.LoadUnitConfig()
 
-	admin_model.RemoveAllWithNotice("Clean up repository temporary data", filepath.Join(setting.AppDataPath, "tmp"))
+	admin_model.RemoveAllWithNotice(db.DefaultContext, "Clean up repository temporary data", filepath.Join(setting.AppDataPath, "tmp"))
 }
 
 // RepositoryStatus defines the status of repository
@@ -1649,36 +1649,36 @@ func DeleteRepository(doer *User, uid, repoID int64) error {
 
 	// Remove repository files.
 	repoPath := repo.RepoPath()
-	admin_model.RemoveAllWithNotice("Delete repository files", repoPath)
+	admin_model.RemoveAllWithNotice(db.DefaultContext, "Delete repository files", repoPath)
 
 	// Remove wiki files
 	if repo.HasWiki() {
-		admin_model.RemoveAllWithNotice("Delete repository wiki", repo.WikiPath())
+		admin_model.RemoveAllWithNotice(db.DefaultContext, "Delete repository wiki", repo.WikiPath())
 	}
 
 	// Remove archives
 	for i := range archivePaths {
-		admin_model.RemoveStorageWithNotice(storage.RepoArchives, "Delete repo archive file", archivePaths[i])
+		admin_model.RemoveStorageWithNotice(db.DefaultContext, storage.RepoArchives, "Delete repo archive file", archivePaths[i])
 	}
 
 	// Remove lfs objects
 	for i := range lfsPaths {
-		admin_model.RemoveStorageWithNotice(storage.LFS, "Delete orphaned LFS file", lfsPaths[i])
+		admin_model.RemoveStorageWithNotice(db.DefaultContext, storage.LFS, "Delete orphaned LFS file", lfsPaths[i])
 	}
 
 	// Remove issue attachment files.
 	for i := range attachmentPaths {
-		admin_model.RemoveStorageWithNotice(storage.Attachments, "Delete issue attachment", attachmentPaths[i])
+		admin_model.RemoveStorageWithNotice(db.DefaultContext, storage.Attachments, "Delete issue attachment", attachmentPaths[i])
 	}
 
 	// Remove release attachment files.
 	for i := range releaseAttachments {
-		admin_model.RemoveStorageWithNotice(storage.Attachments, "Delete release attachment", releaseAttachments[i])
+		admin_model.RemoveStorageWithNotice(db.DefaultContext, storage.Attachments, "Delete release attachment", releaseAttachments[i])
 	}
 
 	// Remove attachment with no issue_id and release_id.
 	for i := range newAttachmentPaths {
-		admin_model.RemoveStorageWithNotice(storage.Attachments, "Delete issue attachment", attachmentPaths[i])
+		admin_model.RemoveStorageWithNotice(db.DefaultContext, storage.Attachments, "Delete issue attachment", attachmentPaths[i])
 	}
 
 	if len(repo.Avatar) > 0 {
@@ -1803,8 +1803,8 @@ func getPrivateRepositoryCount(e db.Engine, u *User) (int64, error) {
 }
 
 // GetRepositoryCount returns the total number of repositories of user.
-func GetRepositoryCount(u *User) (int64, error) {
-	return getRepositoryCount(db.GetEngine(db.DefaultContext), u)
+func GetRepositoryCount(ctx context.Context, u *User) (int64, error) {
+	return getRepositoryCount(db.GetEngine(ctx), u)
 }
 
 // GetPublicRepositoryCount returns the total number of public repositories of user.
diff --git a/models/repo_test.go b/models/repo_test.go
index 685570adc8..e6f4ea1c3f 100644
--- a/models/repo_test.go
+++ b/models/repo_test.go
@@ -71,7 +71,7 @@ func TestMetas(t *testing.T) {
 func TestGetRepositoryCount(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
-	count, err1 := GetRepositoryCount(&User{ID: int64(10)})
+	count, err1 := GetRepositoryCount(db.DefaultContext, &User{ID: int64(10)})
 	privateCount, err2 := GetPrivateRepositoryCount(&User{ID: int64(10)})
 	publicCount, err3 := GetPublicRepositoryCount(&User{ID: int64(10)})
 	assert.NoError(t, err1)
diff --git a/models/user.go b/models/user.go
index cc6c5a5578..1bdb435793 100644
--- a/models/user.go
+++ b/models/user.go
@@ -22,7 +22,6 @@ import (
 
 	_ "image/jpeg" // Needed for jpeg support
 
-	admin_model "code.gitea.io/gitea/models/admin"
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/login"
 	"code.gitea.io/gitea/models/unit"
@@ -32,7 +31,6 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
-	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/util"
@@ -542,15 +540,16 @@ func (u *User) IsPublicMember(orgID int64) bool {
 	return isMember
 }
 
-func (u *User) getOrganizationCount(e db.Engine) (int64, error) {
-	return e.
+// GetOrganizationCount returns count of membership of organization of the user.
+func GetOrganizationCount(ctx context.Context, u *User) (int64, error) {
+	return db.GetEngine(ctx).
 		Where("uid=?", u.ID).
 		Count(new(OrgUser))
 }
 
 // GetOrganizationCount returns count of membership of organization of user.
 func (u *User) GetOrganizationCount() (int64, error) {
-	return u.getOrganizationCount(db.GetEngine(db.DefaultContext))
+	return GetOrganizationCount(db.DefaultContext, u)
 }
 
 // GetRepositories returns repositories that user owns, including private repositories.
@@ -1149,26 +1148,9 @@ func deleteBeans(e db.Engine, beans ...interface{}) (err error) {
 	return nil
 }
 
-func deleteUser(ctx context.Context, u *User) error {
+// DeleteUser deletes models associated to an user.
+func DeleteUser(ctx context.Context, u *User) (err error) {
 	e := db.GetEngine(ctx)
-	// Note: A user owns any repository or belongs to any organization
-	//	cannot perform delete operation.
-
-	// Check ownership of repository.
-	count, err := getRepositoryCount(e, u)
-	if err != nil {
-		return fmt.Errorf("GetRepositoryCount: %v", err)
-	} else if count > 0 {
-		return ErrUserOwnRepos{UID: u.ID}
-	}
-
-	// Check membership of organization.
-	count, err = u.getOrganizationCount(e)
-	if err != nil {
-		return fmt.Errorf("GetOrganizationCount: %v", err)
-	} else if count > 0 {
-		return ErrUserHasOrgs{UID: u.ID}
-	}
 
 	// ***** START: Watch *****
 	watchedRepoIDs := make([]int64, 0, 10)
@@ -1301,85 +1283,21 @@ func deleteUser(ctx context.Context, u *User) error {
 		return fmt.Errorf("Delete: %v", err)
 	}
 
-	// Note: There are something just cannot be roll back,
-	//	so just keep error logs of those operations.
-	path := UserPath(u.Name)
-	if err = util.RemoveAll(path); err != nil {
-		err = fmt.Errorf("Failed to RemoveAll %s: %v", path, err)
-		_ = admin_model.CreateNoticeCtx(ctx, admin_model.NoticeTask, fmt.Sprintf("delete user '%s': %v", u.Name, err))
-		return err
-	}
-
-	if len(u.Avatar) > 0 {
-		avatarPath := u.CustomAvatarRelativePath()
-		if err = storage.Avatars.Delete(avatarPath); err != nil {
-			err = fmt.Errorf("Failed to remove %s: %v", avatarPath, err)
-			_ = admin_model.CreateNoticeCtx(ctx, admin_model.NoticeTask, fmt.Sprintf("delete user '%s': %v", u.Name, err))
-			return err
-		}
-	}
-
 	return nil
 }
 
-// DeleteUser completely and permanently deletes everything of a user,
-// but issues/comments/pulls will be kept and shown as someone has been deleted,
-// unless the user is younger than USER_DELETE_WITH_COMMENTS_MAX_DAYS.
-func DeleteUser(u *User) (err error) {
-	if u.IsOrganization() {
-		return fmt.Errorf("%s is an organization not a user", u.Name)
-	}
+// GetInactiveUsers gets all inactive users
+func GetInactiveUsers(ctx context.Context, olderThan time.Duration) ([]*User, error) {
+	var cond builder.Cond = builder.Eq{"is_active": false}
 
-	ctx, committer, err := db.TxContext()
-	if err != nil {
-		return err
-	}
-	defer committer.Close()
-
-	if err = deleteUser(ctx, u); err != nil {
-		// Note: don't wrapper error here.
-		return err
-	}
-
-	return committer.Commit()
-}
-
-// DeleteInactiveUsers deletes all inactive users and email addresses.
-func DeleteInactiveUsers(ctx context.Context, olderThan time.Duration) (err error) {
-	users := make([]*User, 0, 10)
 	if olderThan > 0 {
-		if err = db.GetEngine(db.DefaultContext).
-			Where("is_active = ? and created_unix < ?", false, time.Now().Add(-olderThan).Unix()).
-			Find(&users); err != nil {
-			return fmt.Errorf("get all inactive users: %v", err)
-		}
-	} else {
-		if err = db.GetEngine(db.DefaultContext).
-			Where("is_active = ?", false).
-			Find(&users); err != nil {
-			return fmt.Errorf("get all inactive users: %v", err)
-		}
-	}
-	// FIXME: should only update authorized_keys file once after all deletions.
-	for _, u := range users {
-		select {
-		case <-ctx.Done():
-			return db.ErrCancelledf("Before delete inactive user %s", u.Name)
-		default:
-		}
-		if err = DeleteUser(u); err != nil {
-			// Ignore users that were set inactive by admin.
-			if IsErrUserOwnRepos(err) || IsErrUserHasOrgs(err) {
-				continue
-			}
-			return err
-		}
+		cond = cond.And(builder.Lt{"created_unix": time.Now().Add(-olderThan).Unix()})
 	}
 
-	_, err = db.GetEngine(db.DefaultContext).
-		Where("is_activated = ?", false).
-		Delete(new(user_model.EmailAddress))
-	return err
+	users := make([]*User, 0, 10)
+	return users, db.GetEngine(ctx).
+		Where(cond).
+		Find(&users)
 }
 
 // UserPath returns the path absolute path of user repositories.
diff --git a/models/user/email_address.go b/models/user/email_address.go
index 74fb71d454..98cd14a6a5 100644
--- a/models/user/email_address.go
+++ b/models/user/email_address.go
@@ -267,3 +267,11 @@ func DeleteEmailAddresses(emails []*EmailAddress) (err error) {
 
 	return nil
 }
+
+// DeleteInactiveEmailAddresses deletes inactive email addresses
+func DeleteInactiveEmailAddresses(ctx context.Context) error {
+	_, err := db.GetEngine(ctx).
+		Where("is_activated = ?", false).
+		Delete(new(EmailAddress))
+	return err
+}
diff --git a/models/user_test.go b/models/user_test.go
index 4e2e521767..2da5519d74 100644
--- a/models/user_test.go
+++ b/models/user_test.go
@@ -177,41 +177,6 @@ func TestSearchUsers(t *testing.T) {
 		[]int64{24})
 }
 
-func TestDeleteUser(t *testing.T) {
-	test := func(userID int64) {
-		assert.NoError(t, unittest.PrepareTestDatabase())
-		user := unittest.AssertExistsAndLoadBean(t, &User{ID: userID}).(*User)
-
-		ownedRepos := make([]*Repository, 0, 10)
-		assert.NoError(t, db.GetEngine(db.DefaultContext).Find(&ownedRepos, &Repository{OwnerID: userID}))
-		if len(ownedRepos) > 0 {
-			err := DeleteUser(user)
-			assert.Error(t, err)
-			assert.True(t, IsErrUserOwnRepos(err))
-			return
-		}
-
-		orgUsers := make([]*OrgUser, 0, 10)
-		assert.NoError(t, db.GetEngine(db.DefaultContext).Find(&orgUsers, &OrgUser{UID: userID}))
-		for _, orgUser := range orgUsers {
-			if err := RemoveOrgUser(orgUser.OrgID, orgUser.UID); err != nil {
-				assert.True(t, IsErrLastOrgOwner(err))
-				return
-			}
-		}
-		assert.NoError(t, DeleteUser(user))
-		unittest.AssertNotExistsBean(t, &User{ID: userID})
-		unittest.CheckConsistencyFor(t, &User{}, &Repository{})
-	}
-	test(2)
-	test(4)
-	test(8)
-	test(11)
-
-	org := unittest.AssertExistsAndLoadBean(t, &User{ID: 3}).(*User)
-	assert.Error(t, DeleteUser(org))
-}
-
 func TestEmailNotificationPreferences(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
@@ -333,21 +298,6 @@ func TestDisplayName(t *testing.T) {
 	}
 }
 
-func TestCreateUser(t *testing.T) {
-	user := &User{
-		Name:               "GiteaBot",
-		Email:              "GiteaBot@gitea.io",
-		Passwd:             ";p['////..-++']",
-		IsAdmin:            false,
-		Theme:              setting.UI.DefaultTheme,
-		MustChangePassword: false,
-	}
-
-	assert.NoError(t, CreateUser(user))
-
-	assert.NoError(t, DeleteUser(user))
-}
-
 func TestCreateUserInvalidEmail(t *testing.T) {
 	user := &User{
 		Name:               "GiteaBot",
@@ -363,36 +313,6 @@ func TestCreateUserInvalidEmail(t *testing.T) {
 	assert.True(t, user_model.IsErrEmailInvalid(err))
 }
 
-func TestCreateUser_Issue5882(t *testing.T) {
-	// Init settings
-	_ = setting.Admin
-
-	passwd := ".//.;1;;//.,-=_"
-
-	tt := []struct {
-		user               *User
-		disableOrgCreation bool
-	}{
-		{&User{Name: "GiteaBot", Email: "GiteaBot@gitea.io", Passwd: passwd, MustChangePassword: false}, false},
-		{&User{Name: "GiteaBot2", Email: "GiteaBot2@gitea.io", Passwd: passwd, MustChangePassword: false}, true},
-	}
-
-	setting.Service.DefaultAllowCreateOrganization = true
-
-	for _, v := range tt {
-		setting.Admin.DisableRegularOrgCreation = v.disableOrgCreation
-
-		assert.NoError(t, CreateUser(v.user))
-
-		u, err := GetUserByEmail(v.user.Email)
-		assert.NoError(t, err)
-
-		assert.Equal(t, !u.AllowCreateOrganization, v.disableOrgCreation)
-
-		assert.NoError(t, DeleteUser(v.user))
-	}
-}
-
 func TestGetUserIDsByNames(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
diff --git a/modules/repository/create_test.go b/modules/repository/create_test.go
index 2e27ab0d7d..55fc515588 100644
--- a/modules/repository/create_test.go
+++ b/modules/repository/create_test.go
@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/unittest"
 	"code.gitea.io/gitea/modules/structs"
 
@@ -142,5 +143,5 @@ func TestIncludesAllRepositoriesTeams(t *testing.T) {
 			assert.NoError(t, models.DeleteRepository(user, org.ID, rid), "DeleteRepository %d", i)
 		}
 	}
-	assert.NoError(t, models.DeleteOrganization(org), "DeleteOrganization")
+	assert.NoError(t, models.DeleteOrganization(db.DefaultContext, org), "DeleteOrganization")
 }
diff --git a/routers/api/v1/admin/user.go b/routers/api/v1/admin/user.go
index 1e4a2851c2..95060e7a1c 100644
--- a/routers/api/v1/admin/user.go
+++ b/routers/api/v1/admin/user.go
@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/routers/api/v1/user"
 	"code.gitea.io/gitea/routers/api/v1/utils"
 	"code.gitea.io/gitea/services/mailer"
+	user_service "code.gitea.io/gitea/services/user"
 )
 
 func parseLoginSource(ctx *context.APIContext, u *models.User, sourceID int64, loginName string) {
@@ -289,7 +290,7 @@ func DeleteUser(ctx *context.APIContext) {
 		return
 	}
 
-	if err := models.DeleteUser(u); err != nil {
+	if err := user_service.DeleteUser(u); err != nil {
 		if models.IsErrUserOwnRepos(err) ||
 			models.IsErrUserHasOrgs(err) {
 			ctx.Error(http.StatusUnprocessableEntity, "", err)
diff --git a/routers/api/v1/org/org.go b/routers/api/v1/org/org.go
index d3aa92f46d..e82e8552e0 100644
--- a/routers/api/v1/org/org.go
+++ b/routers/api/v1/org/org.go
@@ -16,6 +16,7 @@ import (
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/api/v1/user"
 	"code.gitea.io/gitea/routers/api/v1/utils"
+	"code.gitea.io/gitea/services/org"
 )
 
 func listUserOrgs(ctx *context.APIContext, u *models.User) {
@@ -364,7 +365,7 @@ func Delete(ctx *context.APIContext) {
 	//   "204":
 	//     "$ref": "#/responses/empty"
 
-	if err := models.DeleteOrganization(ctx.Org.Organization); err != nil {
+	if err := org.DeleteOrganization(ctx.Org.Organization); err != nil {
 		ctx.Error(http.StatusInternalServerError, "DeleteOrganization", err)
 		return
 	}
diff --git a/routers/web/admin/users.go b/routers/web/admin/users.go
index 93e59893e9..b23e4cf39b 100644
--- a/routers/web/admin/users.go
+++ b/routers/web/admin/users.go
@@ -26,6 +26,7 @@ import (
 	router_user_setting "code.gitea.io/gitea/routers/web/user/setting"
 	"code.gitea.io/gitea/services/forms"
 	"code.gitea.io/gitea/services/mailer"
+	"code.gitea.io/gitea/services/user"
 )
 
 const (
@@ -377,7 +378,7 @@ func DeleteUser(ctx *context.Context) {
 		return
 	}
 
-	if err = models.DeleteUser(u); err != nil {
+	if err = user.DeleteUser(u); err != nil {
 		switch {
 		case models.IsErrUserOwnRepos(err):
 			ctx.Flash.Error(ctx.Tr("admin.users.still_own_repo"))
diff --git a/routers/web/org/setting.go b/routers/web/org/setting.go
index 53c31a1c60..f27cb40838 100644
--- a/routers/web/org/setting.go
+++ b/routers/web/org/setting.go
@@ -20,6 +20,7 @@ import (
 	"code.gitea.io/gitea/modules/web"
 	userSetting "code.gitea.io/gitea/routers/web/user/setting"
 	"code.gitea.io/gitea/services/forms"
+	"code.gitea.io/gitea/services/org"
 )
 
 const (
@@ -156,15 +157,14 @@ func SettingsDelete(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("org.settings")
 	ctx.Data["PageIsSettingsDelete"] = true
 
-	org := ctx.Org.Organization
 	if ctx.Req.Method == "POST" {
-		if org.Name != ctx.FormString("org_name") {
+		if ctx.Org.Organization.Name != ctx.FormString("org_name") {
 			ctx.Data["Err_OrgName"] = true
 			ctx.RenderWithErr(ctx.Tr("form.enterred_invalid_org_name"), tplSettingsDelete, nil)
 			return
 		}
 
-		if err := models.DeleteOrganization(org); err != nil {
+		if err := org.DeleteOrganization(ctx.Org.Organization); err != nil {
 			if models.IsErrUserOwnRepos(err) {
 				ctx.Flash.Error(ctx.Tr("form.org_still_own_repo"))
 				ctx.Redirect(ctx.Org.OrgLink + "/settings/delete")
@@ -172,7 +172,7 @@ func SettingsDelete(ctx *context.Context) {
 				ctx.ServerError("DeleteOrganization", err)
 			}
 		} else {
-			log.Trace("Organization deleted: %s", org.Name)
+			log.Trace("Organization deleted: %s", ctx.Org.Organization.Name)
 			ctx.Redirect(setting.AppSubURL + "/")
 		}
 		return
diff --git a/routers/web/user/setting/account.go b/routers/web/user/setting/account.go
index 5ef1c3bdc8..3362d3806d 100644
--- a/routers/web/user/setting/account.go
+++ b/routers/web/user/setting/account.go
@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/services/auth"
 	"code.gitea.io/gitea/services/forms"
 	"code.gitea.io/gitea/services/mailer"
+	"code.gitea.io/gitea/services/user"
 )
 
 const (
@@ -241,7 +242,7 @@ func DeleteAccount(ctx *context.Context) {
 		return
 	}
 
-	if err := models.DeleteUser(ctx.User); err != nil {
+	if err := user.DeleteUser(ctx.User); err != nil {
 		switch {
 		case models.IsErrUserOwnRepos(err):
 			ctx.Flash.Error(ctx.Tr("form.still_own_repo"))
diff --git a/services/cron/tasks.go b/services/cron/tasks.go
index d29bf6d6bd..732eead930 100644
--- a/services/cron/tasks.go
+++ b/services/cron/tasks.go
@@ -90,18 +90,18 @@ func (t *Task) RunWithUser(doer *models.User, config Config) {
 		if err := t.fun(ctx, doer, config); err != nil {
 			if db.IsErrCancelled(err) {
 				message := err.(db.ErrCancelled).Message
-				if err := admin_model.CreateNotice(admin_model.NoticeTask, config.FormatMessage(t.Name, "aborted", doer, message)); err != nil {
+				if err := admin_model.CreateNotice(ctx, admin_model.NoticeTask, config.FormatMessage(t.Name, "aborted", doer, message)); err != nil {
 					log.Error("CreateNotice: %v", err)
 				}
 				return
 			}
-			if err := admin_model.CreateNotice(admin_model.NoticeTask, config.FormatMessage(t.Name, "error", doer, err)); err != nil {
+			if err := admin_model.CreateNotice(ctx, admin_model.NoticeTask, config.FormatMessage(t.Name, "error", doer, err)); err != nil {
 				log.Error("CreateNotice: %v", err)
 			}
 			return
 		}
 		if config.DoNoticeOnSuccess() {
-			if err := admin_model.CreateNotice(admin_model.NoticeTask, config.FormatMessage(t.Name, "finished", doer)); err != nil {
+			if err := admin_model.CreateNotice(ctx, admin_model.NoticeTask, config.FormatMessage(t.Name, "finished", doer)); err != nil {
 				log.Error("CreateNotice: %v", err)
 			}
 		}
diff --git a/services/cron/tasks_extended.go b/services/cron/tasks_extended.go
index 1f115de43a..b0cb5ee921 100644
--- a/services/cron/tasks_extended.go
+++ b/services/cron/tasks_extended.go
@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/updatechecker"
 	repo_service "code.gitea.io/gitea/services/repository"
+	user_service "code.gitea.io/gitea/services/user"
 )
 
 func registerDeleteInactiveUsers() {
@@ -25,7 +26,7 @@ func registerDeleteInactiveUsers() {
 		OlderThan: 0 * time.Second,
 	}, func(ctx context.Context, _ *models.User, config Config) error {
 		olderThanConfig := config.(*OlderThanConfig)
-		return models.DeleteInactiveUsers(ctx, olderThanConfig.OlderThan)
+		return user_service.DeleteInactiveUsers(ctx, olderThanConfig.OlderThan)
 	})
 }
 
diff --git a/services/org/org.go b/services/org/org.go
new file mode 100644
index 0000000000..cb1f1eca03
--- /dev/null
+++ b/services/org/org.go
@@ -0,0 +1,61 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package org
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/storage"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// DeleteOrganization completely and permanently deletes everything of organization.
+func DeleteOrganization(org *models.User) error {
+	if !org.IsOrganization() {
+		return fmt.Errorf("%s is a user not an organization", org.Name)
+	}
+
+	ctx, commiter, err := db.TxContext()
+	if err != nil {
+		return err
+	}
+	defer commiter.Close()
+
+	// Check ownership of repository.
+	count, err := models.GetRepositoryCount(ctx, org)
+	if err != nil {
+		return fmt.Errorf("GetRepositoryCount: %v", err)
+	} else if count > 0 {
+		return models.ErrUserOwnRepos{UID: org.ID}
+	}
+
+	if err := models.DeleteOrganization(ctx, org); err != nil {
+		return fmt.Errorf("DeleteOrganization: %v", err)
+	}
+
+	if err := commiter.Commit(); err != nil {
+		return err
+	}
+
+	// FIXME: system notice
+	// Note: There are something just cannot be roll back,
+	//	so just keep error logs of those operations.
+	path := models.UserPath(org.Name)
+
+	if err := util.RemoveAll(path); err != nil {
+		return fmt.Errorf("Failed to RemoveAll %s: %v", path, err)
+	}
+
+	if len(org.Avatar) > 0 {
+		avatarPath := org.CustomAvatarRelativePath()
+		if err := storage.Avatars.Delete(avatarPath); err != nil {
+			return fmt.Errorf("Failed to remove %s: %v", avatarPath, err)
+		}
+	}
+
+	return nil
+}
diff --git a/services/org/org_test.go b/services/org/org_test.go
new file mode 100644
index 0000000000..5fec086d10
--- /dev/null
+++ b/services/org/org_test.go
@@ -0,0 +1,37 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package org
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/unittest"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m, filepath.Join("..", ".."))
+}
+
+func TestDeleteOrganization(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	org := unittest.AssertExistsAndLoadBean(t, &models.User{ID: 6}).(*models.User)
+	assert.NoError(t, DeleteOrganization(org))
+	unittest.AssertNotExistsBean(t, &models.User{ID: 6})
+	unittest.AssertNotExistsBean(t, &models.OrgUser{OrgID: 6})
+	unittest.AssertNotExistsBean(t, &models.Team{OrgID: 6})
+
+	org = unittest.AssertExistsAndLoadBean(t, &models.User{ID: 3}).(*models.User)
+	err := DeleteOrganization(org)
+	assert.Error(t, err)
+	assert.True(t, models.IsErrUserOwnRepos(err))
+
+	user := unittest.AssertExistsAndLoadBean(t, &models.User{ID: 5}).(*models.User)
+	assert.Error(t, DeleteOrganization(user))
+	unittest.CheckConsistencyFor(t, &models.User{}, &models.Team{})
+}
diff --git a/services/user/user.go b/services/user/user.go
new file mode 100644
index 0000000000..a08e40f86e
--- /dev/null
+++ b/services/user/user.go
@@ -0,0 +1,106 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package user
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"code.gitea.io/gitea/models"
+	admin_model "code.gitea.io/gitea/models/admin"
+	"code.gitea.io/gitea/models/db"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/storage"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// DeleteUser completely and permanently deletes everything of a user,
+// but issues/comments/pulls will be kept and shown as someone has been deleted,
+// unless the user is younger than USER_DELETE_WITH_COMMENTS_MAX_DAYS.
+func DeleteUser(u *models.User) error {
+	if u.IsOrganization() {
+		return fmt.Errorf("%s is an organization not a user", u.Name)
+	}
+
+	ctx, commiter, err := db.TxContext()
+	if err != nil {
+		return err
+	}
+	defer commiter.Close()
+
+	// Note: A user owns any repository or belongs to any organization
+	//	cannot perform delete operation.
+
+	// Check ownership of repository.
+	count, err := models.GetRepositoryCount(ctx, u)
+	if err != nil {
+		return fmt.Errorf("GetRepositoryCount: %v", err)
+	} else if count > 0 {
+		return models.ErrUserOwnRepos{UID: u.ID}
+	}
+
+	// Check membership of organization.
+	count, err = models.GetOrganizationCount(ctx, u)
+	if err != nil {
+		return fmt.Errorf("GetOrganizationCount: %v", err)
+	} else if count > 0 {
+		return models.ErrUserHasOrgs{UID: u.ID}
+	}
+
+	if err := models.DeleteUser(ctx, u); err != nil {
+		return fmt.Errorf("DeleteUser: %v", err)
+	}
+
+	if err := commiter.Commit(); err != nil {
+		return err
+	}
+
+	// Note: There are something just cannot be roll back,
+	//	so just keep error logs of those operations.
+	path := models.UserPath(u.Name)
+	if err := util.RemoveAll(path); err != nil {
+		err = fmt.Errorf("Failed to RemoveAll %s: %v", path, err)
+		_ = admin_model.CreateNotice(db.DefaultContext, admin_model.NoticeTask, fmt.Sprintf("delete user '%s': %v", u.Name, err))
+		return err
+	}
+
+	if u.Avatar != "" {
+		avatarPath := u.CustomAvatarRelativePath()
+		if err := storage.Avatars.Delete(avatarPath); err != nil {
+			err = fmt.Errorf("Failed to remove %s: %v", avatarPath, err)
+			_ = admin_model.CreateNotice(db.DefaultContext, admin_model.NoticeTask, fmt.Sprintf("delete user '%s': %v", u.Name, err))
+			return err
+		}
+	}
+
+	return nil
+}
+
+// DeleteInactiveUsers deletes all inactive users and email addresses.
+func DeleteInactiveUsers(ctx context.Context, olderThan time.Duration) error {
+	users, err := models.GetInactiveUsers(ctx, olderThan)
+	if err != nil {
+		return err
+	}
+
+	// FIXME: should only update authorized_keys file once after all deletions.
+	for _, u := range users {
+		select {
+		case <-ctx.Done():
+			return db.ErrCancelledf("Before delete inactive user %s", u.Name)
+		default:
+		}
+		if err := DeleteUser(u); err != nil {
+			// Ignore users that were set inactive by admin.
+			if models.IsErrUserOwnRepos(err) || models.IsErrUserHasOrgs(err) {
+				continue
+			}
+			return err
+		}
+	}
+
+	return user_model.DeleteInactiveEmailAddresses(ctx)
+}
diff --git a/services/user/user_test.go b/services/user/user_test.go
new file mode 100644
index 0000000000..9162273fae
--- /dev/null
+++ b/services/user/user_test.go
@@ -0,0 +1,101 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package user
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m, filepath.Join("..", ".."))
+}
+
+func TestDeleteUser(t *testing.T) {
+	test := func(userID int64) {
+		assert.NoError(t, unittest.PrepareTestDatabase())
+		user := unittest.AssertExistsAndLoadBean(t, &models.User{ID: userID}).(*models.User)
+
+		ownedRepos := make([]*models.Repository, 0, 10)
+		assert.NoError(t, db.GetEngine(db.DefaultContext).Find(&ownedRepos, &models.Repository{OwnerID: userID}))
+		if len(ownedRepos) > 0 {
+			err := DeleteUser(user)
+			assert.Error(t, err)
+			assert.True(t, models.IsErrUserOwnRepos(err))
+			return
+		}
+
+		orgUsers := make([]*models.OrgUser, 0, 10)
+		assert.NoError(t, db.GetEngine(db.DefaultContext).Find(&orgUsers, &models.OrgUser{UID: userID}))
+		for _, orgUser := range orgUsers {
+			if err := models.RemoveOrgUser(orgUser.OrgID, orgUser.UID); err != nil {
+				assert.True(t, models.IsErrLastOrgOwner(err))
+				return
+			}
+		}
+		assert.NoError(t, DeleteUser(user))
+		unittest.AssertNotExistsBean(t, &models.User{ID: userID})
+		unittest.CheckConsistencyFor(t, &models.User{}, &models.Repository{})
+	}
+	test(2)
+	test(4)
+	test(8)
+	test(11)
+
+	org := unittest.AssertExistsAndLoadBean(t, &models.User{ID: 3}).(*models.User)
+	assert.Error(t, DeleteUser(org))
+}
+
+func TestCreateUser(t *testing.T) {
+	user := &models.User{
+		Name:               "GiteaBot",
+		Email:              "GiteaBot@gitea.io",
+		Passwd:             ";p['////..-++']",
+		IsAdmin:            false,
+		Theme:              setting.UI.DefaultTheme,
+		MustChangePassword: false,
+	}
+
+	assert.NoError(t, models.CreateUser(user))
+
+	assert.NoError(t, DeleteUser(user))
+}
+
+func TestCreateUser_Issue5882(t *testing.T) {
+	// Init settings
+	_ = setting.Admin
+
+	passwd := ".//.;1;;//.,-=_"
+
+	tt := []struct {
+		user               *models.User
+		disableOrgCreation bool
+	}{
+		{&models.User{Name: "GiteaBot", Email: "GiteaBot@gitea.io", Passwd: passwd, MustChangePassword: false}, false},
+		{&models.User{Name: "GiteaBot2", Email: "GiteaBot2@gitea.io", Passwd: passwd, MustChangePassword: false}, true},
+	}
+
+	setting.Service.DefaultAllowCreateOrganization = true
+
+	for _, v := range tt {
+		setting.Admin.DisableRegularOrgCreation = v.disableOrgCreation
+
+		assert.NoError(t, models.CreateUser(v.user))
+
+		u, err := models.GetUserByEmail(v.user.Email)
+		assert.NoError(t, err)
+
+		assert.Equal(t, !u.AllowCreateOrganization, v.disableOrgCreation)
+
+		assert.NoError(t, DeleteUser(v.user))
+	}
+}
diff --git a/services/wiki/wiki.go b/services/wiki/wiki.go
index 2db982a50f..4c8d7dbc53 100644
--- a/services/wiki/wiki.go
+++ b/services/wiki/wiki.go
@@ -13,6 +13,7 @@ import (
 
 	"code.gitea.io/gitea/models"
 	admin_model "code.gitea.io/gitea/models/admin"
+	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/unit"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
@@ -375,6 +376,6 @@ func DeleteWiki(repo *models.Repository) error {
 		return err
 	}
 
-	admin_model.RemoveAllWithNotice("Delete repository wiki", repo.WikiPath())
+	admin_model.RemoveAllWithNotice(db.DefaultContext, "Delete repository wiki", repo.WikiPath())
 	return nil
 }