Thames Water Ltd’s debt pile rose to £14.7 billion ($18.6 billion) in the first half of the year, as the utility faces increased scrutiny over the stability of its financing structure.

Net debt rose 7% year in the six months to September 30, compared to a year earlier, the company reported on Tuesday. The utility’s board has approved a three-year turnaround plan that will enable Thames to make the huge investments needed to 2030 to improve Britain’s water network.