Before the introduction of NVQ qualifications, City and Guilds qualification were the main certificates and exams which plumbers sat. Older plumbers may be City and Guilds qualified whereas younger plumbers will probably have studied NVQs, or SVQs in Scotland. Most plumbers who do domestic work should be qualified to NVQ level 2 standard, which is roughly equivalent to an A level.
Many go further and take the level 3 exams also. NVQ training is typically done on the job, with the plumber starting off with simple jobs while studying at college in the evening or on a day release programme.