If you can't find a plumber for whatever reason, you can use a drain snake to clear the obstruction. A clogged drain may lead to a flooded basement and thousands of dollars in damages. Drain snakes are inexpensive and easy to use.
And, the report will pinpoint exactly where the problem is - so you won't need to hire a plumber if the problem is just a small one. A CCTV drain survey can also be conducted in areas where a traditional inspection is unable to detect problems.