When water inside pipes gurgles and hisses it is an indication of an airlock in a plumbing system. This can occur when your plumbing system is indirectly affected by low water pressure. This allows air to become trapped in the water system of a house and one or more taps may not work.
The simplest means of getting rid of airlocks is to connect a section of hose from a tap that is directly supplied from the mains to the tap that is affected. Be sure to fix the hose securely with clips to both of the taps.
Turn on the tap that does not work first, then turn on the tap supplied by the mains and allow both to stay on for about 30 seconds. Close the mains supplied tap first and then the affected tap. If your tap still has an airlock then you must repeat the process. Sometimes it takes two to three repeats to rid your system of airlocks.
It is important to know that taps for cold water in the kitchen and bathroom usually take water directly from the mains supply. However, in some cases taps could take cold water from a tank in the loft. In this case, airlocks are cleared when the hose is linked from the tap supplied with pressure from the mains.
A widespread dilemma is for the cold-water storage tank not to fill as fast as it is drained. When a bath is filled, check to see if the tank empties prior to the bath filling as this may drag air into the system. Usually, this happens because the float valve is not operating properly or the stopcock is not sufficiently open.
If there are recurring airlocks in a plumbing system you should attempt to seek out the root of the problem. If the problem becomes persistent it would be wise to seek the advice of a professional plumber.