To be honest, I'm not exactly sure. But it's certainly something our building inspector wanted to inspect. Our regs are inexplicably split between "planning permission" which is issued by the local authority before being allowed to start work - also this includes requiring a flood risk assessment - and "building regulations" which is a different department in the local authority, who inspect the works whilst they are taking place to ensure they are carried out to a standardised code (you can also pay to have the service done privately, which is usually a far better option, and it's what we have done - then they report back to the council with their certificate). It's a minefield!

Does every UK basement have to have a sump pump installed? Just curious - building codes always seem so random.