Gullies can be blocked by:

• Debris: like leaves, twigs, silt and other trash
• Oil and Grease: solidfied oil and grease from drains can create blockages
• Tree roots: Tree roots can grow into pipes, and this restricts water flow
• General Litter: Peoples sometimes flush or put items down the gullies that are not meant to be there.

Prevention

• Regular cleaning: Sweep around gully grids, inspect grates for debris, and clear out gutters regularly
• Inspect Gullies Regularly: Check for slow drainage or bad odors, which could indicate a blockage.  
• Maintain Gutters: Keep gutters clear of leaves, moss, and other debris to prevent them from entering gullies. 
• Boiling Water: Pour boiling water down the drain at least once a month to help dissolve grease and other blockages. 
• Clear Debris: Remove any visible debris from the gully. 
• Contact Professionals: If you can't clear the blockage yourself, consider calling KCC Enviro Services.