Scottish Water has cut leaks by nearly 100 million litres a day despite a rise in burst pipes over the winter.
The organisation's annual review also revealed that it made a surplus of more than £100m last year.
Scottish Water said that on average each householder paid £324 for water and waste water services - £15 less than the typical bill in England.
The publicly-owned body claimed water quality was at an all-time high with 99.83% of samples meeting standards.
The organisation said the surplus of £107m was nearly £20m lower than in the previous year - mainly because of a planned increase in depreciation charges associated with major investment projects.
The report also gave details of how the organisation has met the objectives it was set by the Scottish Government.
Far more has been spent on improvements to the quality of drinking water over the past four years than specified by ministers.
Most other objectives were met but an aim to improving unsatisfactory intermittent discharges was narrowly missed.
Scotland is the only part of Great Britain where the water industry is still in the public sector. Critics have called on the government to consider changing the ownership structure of Scottish Water to give it more financial freedom.