A paper on the supply and demand for training among plumbers, compiled by the Scottish Further Education Funding Council, says that plumbers do not command higher than average salaries, at least in Scotland.
Reports of plumbers earning pound;50,000 a year relate largely to London or to specialists on large projects such as the Scottish Parliament, the council's research found. Average gross annual earnings for full-time plumbers and heating and ventilation engineers are not high - pound;24,995.
The paper also refutes claims of a shortage of plumbers which, it says, may well be due to householders' experiences of being unable to find a plumber in an emergency or out of hours.
"There is a danger that learners may make choices based on incorrect perceptions," it states. "Policy-makers also need to have access to the best available evidence."
The paper found that plumbing has a relatively high share of hard-to-fill vacancies in the construction industry in general, but it is not the worst affected trade. Painting companies, for example, had 300 hard-to-fill vacancies in 2003, according to the Scottish Construction Skills Survey, while plumbing had 142.
Some 1,382 students enrolled on plumbing courses in 17 FE colleges last year, compared with 775 in 1998-99. Last year's intake ranged from 164 in Cardonald College to 31 in Dumfries and Galloway College.
Almost three-quarters of plumbing firms offered their own training, compared to a construction industry average of 51 per cent.