The hydrant network is primarily used for fire protection, then for the needs of maintaining the water supply network, flushing the system and analysing the healthiness of drinking water. Especially in the summer months, the problem of unauthorized opening and theft of water from hydrants often occurs (common reasons are: filling of swimming pools, irrigation of lawn, irrigation of various crops and soil in agriculturally intensive areas, etc.). Such unconscionable and illegal behaviour of individuals significantly endangers the overall stability of the water supply system. Sudden opening and closing of the valve causes strong pressure changes that cause "shocks" in the system, which then often lead to pipe bursts and interruption of the water supply. If luckily the pipe does not burst, there is a sudden decrease in pressure in the system, which often manifests itself as a shortage of water for users in that area. Also, one of the possible consequences of this kind of treatment is the rise of sediment, which results in the appearance of cloudy/murky water for users that is not suitable for consumption. Not least, these procedures directly threaten the possibility of quick and effective fire protection.