Weston, who worked at Centrica for 13 years, will take over as chief executive on January 8, replacing interim co-bosses Cathryn Ross and Alastair Cochran.
They stepped in when former boss Sarah Bentley resigned in June having left the country's largest water supplier on the brink of emergency nationalisation.
Thames Water chairman Adrian Montague said Weston had a "proven track record working in regulated environments, turning round business performance and improving customer experience".
Former soldier Weston said his focus would be on "delivering the turnaround that the business has outlined and improving performance over the next few years."
Cochran on Tuesday told MPs that more time was needed to turn around its fortunes after announcing a slump in profits and mounting debt.
Thames Water supplies 15 million customers in London and the Thames Valley area of southeast England and has net debts of nearly GBP15 billion ($19 billion).
Last week the company said its profit after tax tumbled 57 percent to GBP172.3 million in the six months to the end of September.
Its precarious financial situation worried the government so much earlier this year that it fuelled speculation about a possible public rescue plan.
In July, Thames Water received assurances of GBP750 million of new shareholder funding between now and 2025, short of the GBP1 billion it was seeking on top of the GBP500 million it secured in March.
Thames, which blames its situation on regulatory limits on price increases for customers, says it would need a further GBP2.5 billion of support between 2025 and 2030.
It also wants its creditors to extend the maturity on a debt of GBP190 million, which matures in April next year.
The UK's water companies have been criticised for a number of years for wastewater discharges into rivers and the sea because of a lack of investment in upgrading sewage networks, many of which date from the 19th century.
Improvements will cost billions but the firms have accumulated more than GBP60 billion in debt since they were privatised in 1989 under prime minister Margaret Thatcher.
Related Links
Water News - Science, Technology and Politics
Subscribe Free To Our Daily Newsletters |
Subscribe Free To Our Daily Newsletters |