The common and general plumbing mistake involves the wrong selection of pipes when repairing leaks in your house. This is both in terms of the size & the type of the pipe that is being used. The pipes may therefore fail to fit into each other, as you need. Using too much force when connecting 2 pipes together or forcing the connectors may break the pipes or the pipe connectors. Further leaks may develop in the pipes and they may burst when pressure builds up in the pipe. Corrosion may also occur if you get the pipe type wrong. Professional plumbers know when to use galvanized pipes and when to use the correct copper pipes. Connecting the 2 will lead to corrosion which will require regular replacement of the pipes.
Improvising makeshift tools and equipment in place of what the professional plumber uses is another regular mis happening. For eg, many people use marbles or ball bearings in place of a real level when installing or repairing bathroom fixtures. A ball bearing or marble may not work when checking the level and this could force you into unnecessary common reworks. Getting the level wrong when installing the toilet could also lead to slow flow of sewer or even backups in the plumbing pipes. Using the correct tools for a given task will not only save you time but will also make sure that the pipes do not crack as you are fitting them.
You need to have a good design of where the sewer pipes are to be placed. This is especially the case when carrying out plumbing works in the upper floors of a building or apartment blocks. An odd DIY plumbing mistake involves routing the pipes in the wrong places so that they interfere with occupants of the higher floors of the building. Imagine a situation where you are always woken up by the sound of toilet flushing from the floors above. A common practice by professional plumbers involves designing & planning the drainage network before the implementation.
The last DIY plumbing mistake in the list is failure to turn off the water stopcock before attempting any type of repairs. This is always the first thing that a professional plumber will do even for the tiniest plumbing tasks at. Doing so prevents flooding, which often causes damage to common household items. It will also take you added time to drain the water from the bedroom.
Trying to fix a small problem on your own and getting it wrong could create a major problem. Hiring an emergency plumber to rectify the bigger problem will cost you more money. You should therefore take your time when doing your own plumbing work to avoid such mistakes or call a professional plumber in case you are not sure how to fix the problem