​Nothing screams EMERGENCY like a blocked toilet especially if the kids are due home or you are having friends over. Blocked toilets are most commonly caused by tree roots penetrating the drain pipe however there are also other causes such as sanitary products, toys and the trusty old toilet ducks - a drainage plumbers best friend! Plunging is never a good idea as it only shifts the blockage further along the system. Machining or jetting is the only way to go.