This is a special place where I can recommend personally businesses I have worked with or who do good consistent work. Therefore there is luck involved in my finding and using the services but also they were good at what they do/did. So you can take it from me that they are worth exploring.
It's the one thing that when you get an emergency it's a real emergency and can't wait. The dreaded water damage that can ensue or lack of heating in winter is a real fear. So arm yourself with a few names in case you need a reliable plumber in Cambridge.
I have a simple list of sports-related sites that my friends and people in the business own.