Matt Wilmot, 40, was found by police after reports of concern for the welfare of a man.  He was pronounced dead at the scene, in Devon Road, Luton.
Affinity Water confirmed "the body of a man was found at the bottom of one of our excavations".
Bedfordshire Police said Mr Wilmot's death, at about 07:15 BST on Sunday, was not being treated as suspicious.
The force said it was not possible to speculate on how he died until the coroner's full report had been released.
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It is understood Mr Wilmot, a father-of-two, had been walking home from Dunstable, where he had been watching the FA Cup Final on Saturday afternoon.
Mr Wilmot's partner of 24 years, Tania Banks, said: "I just can't believe that he's gone and the circumstances [in which] he's gone.
"We're just angry at the situation... and how something like this could happen."
The Health and Safety Executive has been informed about the incident, police said.

The biggest is a $47.5bn (Â£38.6bn) civil claim brought by Brazil's federal prosecutors, the companies said.
Under the deal, the firms will provide an initial $681m in compensation.
The collapse of the dam, containing waste from an iron ore mine, killed 19 people and created a river of millions of tonnes of toxic waste.
It killed 19 people and is Brazil's worst ever mine disaster.
The agreement, between the companies and prosecutors, will see experts appointed to advise the federal prosecutors on the impacts of the dam disaster and any changes that might be needed to social and environmental remediation programs agreed last May.
It does not cover the potential size of the final liabilities to be agreed by the end of June.
BHP spokesman, Paul Hitchins, said the settlement simplified matters: "This spells out how and when we are going to settle this with the prosecutors.
"Up until this time we had all these different courts hearing the case. This consolidates all that."
The companies said they still had not agreed how and when the mine would be able to re-open.
They said any restart was subject to separate negotiations and would only happen once it was safe to do so and economically viable.
It also needed the support of the devastated local community.
The body of a man has been found at the bottom of a hole dug by a water firm.
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BHP Billiton and Vale have agreed a deadline of 30 June to consolidate and settle claims resulting from Brazil's Samarco dam disaster in 2015.