Drain - about safety
In some systems the drain is for discharge of waste fluids, such as the drain in a sink in which the water is drained when it is no longer needed.
In the United Kingdom, plumbers refer to waste water as 'bad water'. This is under the premise that the water they are moving from one area to another via the use of a drain is not needed and can be removed from the area, like a 'bad apple' being removed from a fruit bowl.
In other systems, such as fountains or swimming pools where waste fluid is recirculated, the drain is the input to the recirculating pumping machine.
In the last case, there is an obvious safety issue, because many people do not expect to encounter more than the head of water above the drain when touching a drain. For example, in a recent case, a lifeguard went to the bottom of a pool to retrieve something and his hand got stuck because of the extra pressure from the pump. When there is a recirculating pump, the risk of suction consists of the head of water, plus the suction of the pump (up to a maximum of 1 atmosphere).
Źródło: https://en.wikipedia.org/wiki/Drain_(plumbing)
Reliable service hydraulic
The hydraulic system is a very important part of any building, so it's good to care for her. If you are a failure, you should immediately call the appropriate service hydraulic, and at the same time it is necessary to remember that he was a proven and reliable. Only those reputable, recommended by many companies are able to provide us with services of the highest quality, which is why it is good to try when selecting specific professionals. Ideally, it was the service, which have used our friends or that is recommended on internet forums. Only such a professional company will be good, if we want our hydraulic system worked flawlessly.
Repair of small hydraulic failure
Malfunctions related to the plumbing is a real nightmare for the residents of the building. There are often such failures, which for a long time to hinder the normal functioning and cause many other problems, but some of them are too small and can be quickly repaired. It is important, however, that even the smallest failure to call the appropriate professionals, because even if something on the surface it seems to us trivial, inadequately repaired, can result in a much higher failure and pretty large problems. Repair small defects do not pay much, and good specialist will deal with it quickly and professionally. It is so much simpler, cheaper and better solution than self-repair.