Quite a lot of the nationalised water and sewage systems elsewhere in Europe don't even seem to be managing the bare minimum though, it's just that without the privatisation angle the media doesn't care so they appear better. For example, Ireland tried to privatise their water industry a good while back in order to fund necessary investments and gave up due to protests - this was widely seen as a success that protected them from the disaster that hit the UK. Except that they've still completely failed to build basic sewage treatment in a bunch of urban areas that was meant to be built a long time ago according to EU rules, and which the privatised English water companies did manage to build. Plus they have the same problems that British water companies do on top of that. It's just that no privatisation means that there's no easy target to blame that fits people's existing beliefs about the world, so it's not front-page news and most people don't realise it's happening and happily believe their sewage is so much better handled than in stinky Britain.
That being the case then, I wonder what's different about countries that get it right? Better public sector management? Privatisation with stronger regulation?
A well managed parastatal/state owned company. The shareholder returns can be pumped back into the business if they fail and management sacked. A get out of jail free card/the profits aren't being siphoned off to a select few and indirectly, the commodity is potentially cost efficient for consumers.