Tap water quality in England and Wales is at an all time high, according to a watchdog report.
Nearly all the water tested last year met national and European Union standards proving the public can trust their supply, said the Drinking Water Inspectorate (DWI).
A total of 99.87% of 2.9 million tests on water in England and Wales last year met the standards - compared to 99.86% the previous year.
Water from 26 water companies supplying 52.7 million people, was tested.
Jeni Colbourne, the DWI's new chief inspector, said: "We have one of the strictest drinking water safety regimes in the world, and tens of millions of people who drink tap water every day are reaping the
Less than 4,000 samples failed to meet the water quality standard - compared to 37,000 a decade ago.
And none of the failures were serious enough to pose a health risk, the report said.
Nitrite - from disinfectant used to stop bacteria forming between the treatment works and the tap - accounted for most of the breaches in standards.
Bottled water merits
The results prompted the watchdog to question the merit of the £1bn spent by Britons each year on bottled water.
And it pointed out that bottled water is 1,000 times more expensive than tap water.
Deputy chief inspector Claire Jackson said while bottled water had a shelf life of two years tap water was fresh daily.
But the difference between tap and mineral water is clear, said the Natural Mineral Water Information Service.
Spokeswoman Jo Jacobius said: "The choice between the two is whether you want your water naturally clean or chemically cleaned."
Environment Minister Elliot Morley said the findings reflected the rigorous enforcement by DWI.
Ten water companies fell below the 99.87% average for water quality in England
and Wales last year.
They included Anglia Water Services, which scored 99.63%, South East Water
at 99.78%, and United Utilities in north west England at 99.81%.