There are several clues to a blocked soil stack problem, such as foul smells or a toilet that drains slowly.

Unblocking a soil stack is an unpleasant job and it’s worth hiring a professional drain cleaning company. If, however, you want to tackle the problem yourself, you should kit yourself out with protective clothing and a face mask.

If the pipe is made of cast iron, it will almost certainly be cleared via the vent above the roof.

A modern plastic stack is easier to clean as there should be a large hinged cleaning eye, or other access plugs, wherever branch pipes join the stack.

• 1. Unscrew and open the cleaning eye to insert the drain auger
• 2. Pass the auger into the stack until you locate the obstruction then crank the handle to engage it
• 3. Push or pull the auger until you can dislodge the obstruction to clear the trapped water
• 4. Hose out the stack
• 5. Wash and disinfect the surrounding area