There are many things that go into the process of clearing a blocked drain, and one of the most important is to identify what caused it in the first place This can be difficult if there has been extensive damage from human activities or natural disasters such as floods In some cases, however, it may be possible to determine which objects were blocking the drains simply by looking at them If this isn't possible or practical then more sophisticated methods must be used including CCTV footage or hydrology equipment - Pumping devices may need to be brought in specifically for this purpose and operated with care so as not cause further damage or erosion around the blockage; - Excavating machines can also sometimes help free up pipes quickly but should only ever be used when absolutely necessary due to their potential impact on surrounding property; - Other tools that might include jetting systems, water cannons or high pressure hoses can all play a part in getting rid of debris and restoring normal flow through blocked drains; - Finally, workers often have access to specialist knowledge relating either directlyto building engineering (such as closed circuit television)or sanitation (suchas toilet cleaning)