diff --git a/progit/hooks/irc.py b/progit/hooks/irc.py
index cb7f6b6..bb23ae0 100644
--- a/progit/hooks/irc.py
+++ b/progit/hooks/irc.py
@@ -47,7 +47,8 @@ class IrcTable(BASE):
     ssl = sa.Column(sa.Boolean, nullable=False, default=True)
 
     project = relation(
-        'Project', remote_side=[Project.id], backref='irc_hook')
+        'Project', remote_side=[Project.id], backref='irc_hook',
+        cascade="delete, delete-orphan", single_parent=True)
 
 
 class IrcForm(wtf.Form):
diff --git a/progit/hooks/mail.py b/progit/hooks/mail.py
index f95f1e8..77e05be 100644
--- a/progit/hooks/mail.py
+++ b/progit/hooks/mail.py
@@ -42,7 +42,8 @@ class MailTable(BASE):
     active = sa.Column(sa.Boolean, nullable=False, default=False)
 
     project = relation(
-        'Project', remote_side=[Project.id], backref='mail_hook')
+        'Project', remote_side=[Project.id], backref='mail_hook',
+        cascade="delete, delete-orphan", single_parent=True)
 
 
 class MailForm(wtf.Form):
diff --git a/progit/hooks/progit_hook.py b/progit/hooks/progit_hook.py
index aadfae5..197531d 100644
--- a/progit/hooks/progit_hook.py
+++ b/progit/hooks/progit_hook.py
@@ -41,7 +41,8 @@ class ProgitTable(BASE):
     active = sa.Column(sa.Boolean, nullable=False, default=False)
 
     project = relation(
-        'Project', remote_side=[Project.id], backref='progit_hook')
+        'Project', remote_side=[Project.id], backref='progit_hook',
+        cascade="delete, delete-orphan", single_parent=True)
 
 
 class ProgitForm(wtf.Form):
diff --git a/progit/hooks/progit_ticket_hook.py b/progit/hooks/progit_ticket_hook.py
index 7dfdba8..9cb36fb 100644
--- a/progit/hooks/progit_ticket_hook.py
+++ b/progit/hooks/progit_ticket_hook.py
@@ -41,7 +41,8 @@ class ProgitTicketsTable(BASE):
     active = sa.Column(sa.Boolean, nullable=False, default=False)
 
     project = relation(
-        'Project', remote_side=[Project.id], backref='progit_hook_tickets')
+        'Project', remote_side=[Project.id], backref='progit_hook_tickets',
+        cascade="delete, delete-orphan", single_parent=True)
 
 
 class ProgitTicketsForm(wtf.Form):