Analysis found a 40% taxpayer who paid their bonus into a pension ended up with around £57,000 more in their pension after 20 years than someone who overpaid the mortgage.
The new rules, which take effect immediately under the Water (Special Measures) Act, represent a significant shift in the regulation of the water industry.
The bonuses will be distributed based on years of service, with the first £3,600 of each payout tax-free under EOT rules.
The findings have been revealed from global talent solutions business Robert Walters newly launched Salary Survey guide.