[header] How to find a good plumber [title] Check to make sure that they have a plumbing license. [step] The most basic rule is to be sure that they're licensed and carry full insurance that protects you and your neighbour's property in the event of a catastrophe. [title] Get two or more references and read online reviews. 
[step] You can even ask to see some of the work they have done. Read their facebook page and twitter feed to see how they are interacting with their customers [title] Ask how long they have been in business for.