Yorkshire Water has admitted supplying water unfit for human consumption.

The company pleaded guilty at Leeds Crown Court to 17 counts involving the supply of discoloured water in 1997 and 1998 in Boroughbridge, and other counts in Leeds and Bradford.

Judge Norman Jones QC ordered that another 16 counts relating to the supply of water unfit for human consumption in Sheffield, Leeds and Ilkley be left to lie on the file.

The company had already pleaded guilty to 12 charges, and admitted another five today in the light of an earlier ruling by the judge that water could be considered unfit for human consumption if it firstly constitutes a health hazard, or secondly "if a consumer of reasonable firmness might reject it on aesthetic grounds".

Charles Miskin, mitigating, said the company admitted five charges relating to an area of Bradford "on the basis that the water there fell foul of the second rule". The case was adjourned for sentencing until Friday.

It was brought by the Drinking Water Inspectorate, which was set up in 1990 mainly to check that water companies in England and Wales were supplying wholesome drinking water and complying with the Water Supply (Water Quality) Regulations.

At earlier magistrates court hearings, Yorkshire Water challenged whether water that is unpalatable but not unhealthy can be defined as unfit.