Hospitals struggling to provide safe liquids to patients in last summer's floods were let down by an "overstretched and disorganised" water authority, a report revealed today.

A Department of Health report on lessons learned from the 2007 crises reveals trust staff in Gloucestershire were left by Severn Trent Water to "manhandle" 13 tonnes of bottled water themselves in addition to their other duties.

The report, released under the Freedom of Information Act said: "The attitude of the suppliers was that when the deliveries had been discharged at Cheltenham General hospital, it was the hospital's problem from there on in.

"There was therefore effectively no co-ordination of bottled water deliveries, and hospital staff (primarily Estates and Facilities staff) were left to manhandle large numbers of bottled water containers and deliver them to every ward and department where potable water was required."

When the hospital ran out of space for empty bottles, staff were advised to take them home.

When water systems needed to be decontaminated, Severn Trent refused to increase chlorination in line with Department of Health guidelines, the writers said.

That meant 60 trust employees had to spend six weeks "superchlorinating" the water themselves – a total of 3,000 hours works.

Meanwhile at Gloucestershire Royal Hospital the number of water tankers provided was "totally inadequate", with a tanker typically taking two hours to discharge its load.

A Severn Trent Water spokeswoman said today: "We accept that, like many other agencies involved, our plans could have been more robust, and have taken steps to address this.

"We have made improvements in flood defences, in long-term water supply resilience which means we will be able to substitute one key asset with another without loss of supply, and in contingency planning should supplies fail."