I had the same issue (low pressure) when I moved into my walk up flat on the 4th floor a few months ago.
Water pressure was so low it was no fun even taking a shower, running the washing machine was a problem too

Finally installed a pressure pump, and everyone at home is happy again.

PS. I noticed my plumber going around to all the outlet taps, taking them out, cleaning them for any small stones or residue, sticking the end of his pliers into the outlet pipe in the wall to clear any blockage there and re fitting the taps again.

Job well done..