Water takes a long time to disappear from gullies or downspouts.
Water flowing out of the drain rather than in, or sewage backing up when you use indoor plumbing. Top Causes of Clogged External Drains clear outside drain
If manual methods fail, you can try a heavy-duty drain cleaner (often sulphuric acid based) specifically designed for outdoor drains. Water takes a long time to disappear from
A "rotten egg" smell coming from the drain, indicating decomposing organic matter. clear outside drain
Before you start digging, you need to identify the symptoms of a clogged drain: