If your outside drain is smelly or overflows, it is blocked and needs cleaning. Kitchen waste that doesn't break down easily, such as grease or tea leaves, or leaves from nearby trees, can clog the grid or trap of a gully drain.
Put on long rubber gloves and, using a trowel, scoop out any debris. Lift out the grid and wash it thoroughly in a bucket of hot water and detergent.
If this doesn't solve the problem, the U-shaped trap below the grid is probably blocked. Wearing rubber gloves, remove the grid and use an empty tin to remove any debris in the bend of the trap. When the trap is clear, wash it with a hose at high pressure, or pour several buckets of water down it.
It helps to prevent the problem if you clean the grid three or four times a year, to remove grease and potential blockages, and pour domestic bleach over it every couple of weeks.
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