Most domestic buildings built pre-1980 will often have a half-inch/15mm supply pipe. The pipe size on properties thereafter has generally been three quarter inch/25mm, and this is the standard size we still fit today. Many older buildings are now upgrading to this new standard.
Fitting a slightly larger pipe (for instance 1inch/32mm) may enhance the volume of water, however, the pressure will remain the same as the network in the street.
Will a larger pipe increase my water pressure?
This is unlikely, however, it is likely to increase your flow which will often resolve the issue. Generally, a pressure test can be done at the time of an estimate/survey visit.