Low pressure in the water supply system does not allow to fully use household appliances and is a weak place of many old houses, somewhere from savings, or due to the impossibility of complete replacement of the pipeline, is a common occurrence. One way or another, you can try to call the housing and communal services dispatcher, and set out the problem in detail, specialists who explore the water supply and will quite find and eliminate the cause of this phenomenon on your call. If this does not help, then you will have to go to the housing and communal services yourself and write an application, register it and write down the application number (usually the secretary is doing this). Next — you are waiting for the arrival of the same specialists who, if possible, solve your problem. But if this is not in their power, and the water supply in your apartment is in good condition, then it makes sense to think about alternative options.