Regs only apply to new work, they cannot be used retrospectively on existing situations. Many older Victorian Homes have the rainwater, from the front at least, directed out to the pavement/highway, and the rest into a combined sewer. Round here, Northamptonshire County Council have cleverly resurfaced a lot of roads in some of these older streets, built the level up, and blocked the outlets from the original cast pipework from the downpipes running under the pavement. Some have been replaced, elsewhere residents have taken their own action and cut the downpipes above the footpath, fitting a shoe to direct the water away from the buildings.
With new build situations, the drainage hierarchy needs to be applied, with the first option a soakaway. If this is not practical, then a surface water sewer, and if that is also ruled out, then a foul/combined sewer can be used but only as a last resort.