Commuted Sums Tool


Central Bedfordshire Council commissioned Metis to develop a tool to estimate the cost of maintaining traditional and sustainable drainage systems as well as road and other asset types. The tool is used to calculate the commuted sums payable by developers on adoption of assets by the Council.


  • Development of a tool that is easy and intuitive to use
  • Commuted sum calculations based on the most reliable available evidence of the costs of maintaining assets, calculated in line with the latest guidance and best practice
  • Calculations tailored to Central Bedfordshire’s maintenance costs
  • Tool designed to be easily updated, so that the tool can learn as maintenance costs become better understood
  • Commuted sums are calculated in a fair, transparent and auditable way
  • Flexible tool design that allows commuted sums to be aligned to planning policy, for example by building in incentives for preferred design options


This project is delivering multiple benefits for Central Bedfordshire, including:

  • More accurate estimation of the true costs of asset adoption – ensuring sums being charged are fair and defendable, and reflect the true cost of maintaining adopted assets
  • Secured funds – facilitating the delivery of a high level of service into the future
  • Informed decision making – the tool can be used to compare the maintenance cost of different scheme options during the early stages of planning
  • Preferred approaches promoted – for example, the tool allows sustainable drainage systems to be incentivised through reduced commuted sums compared to traditional drainage design


Michael Arthur

Project Director


T: 022 071 4653


Alys Bishop

Sustainable Drainage Engineer

By submitting this form I agree to my details being used in sole connection with the intended enquiry. Please check our privacy policy to see how we protect and manage your submitted data.