Kimberly Darroch, whose 10-year-old daughter Milly Main died in the Queen Elizabeth University Hospital (QEUH) in Glasgow after contracting an infection, has launched legal action against NHS Greater Glasgow and Clyde.
Ms Darroch believes Milly, who was recovering from leukaemia treatment, died as a result of contaminated water at the £842 million hospital.
An independent review published in June said there were a "series of problems" with the design and build of the Glasgow hospital campus - but no clear evidence to link those failures to any "avoidable deaths".
Ms Darroch told the Scottish Sun: “We still feel in the dark about what happened to our beloved daughter.
“It’s incredibly painful to relive our ordeal, but we are determined to deliver justice for Milly and answers for all affected patients and parents.
“Our hope is that by taking action we can ensure no other family ever has to go through what we did.”
A spokeswoman for NHS Greater Glasgow and Clyde said: “We continue to offer our sympathies to Milly Main’s family for their loss.
“We remain keen to meet with Milly’s family and we would be happy to arrange this if they would like to discuss Milly’s care.”
An inquiry was launched by Health Secretary Jeane Freeman last year after the deaths of two adults and a child from infections at the hospital.
The investigation started last month and is chaired by Lord Brodie.
Delays to the Royal Hospital for Children and Young People in Edinburgh will also be scrutinised.