SPARE THE ROD
A blocked sewer drain can be a problem if you don’t have plumbing rods. Here’s a handy alternative plan.
Take a length of 20 mm black irrigation pipe. It is firm enough to put into the drain, and inserted into the outflow pipe as far as it will travel.
Now, take your garden hose and insert it into the irrigation pipe, also as far as possible. Turn the water on full.
The hose pipe itself is not firm enough to be fed into the blocked sewer, but using the irrigation pipe allows it to travel much further down the blocked drain.
I have found this very useful.