Policy CC/WE requires developments to meet high standards of water efficiency, with residential development designed to achieve a standard of 80 litres/person/day unless demonstrate impracticable.
It is acknowledged that there are issues with current over-abstraction of the Chalk aquifer and this is having a detrimental impact on environmental conditions. It is also understood that, to address this, Greater Cambridge are seeking to adhere to ambitious water efficiency targets.
The Aspinall Verdi Viability Study (2021) states that an “extra over cost has been included for additional water standards costs with reference to Code for Sustainable Homes levels 5 and 6 (Housing Standards Review Cost Impacts report, DCLG 2014). Baseline allowance of £9 per unit to Code levels 3 & 4, and £2,697 to achieve Code levels 5 & 6 based on Department of Communities and Local Government Housing Standards Review Cost Impact, September 2014 by EC Harris.”
It is noted that these cost figures are greater than 7 years out of date, and whilst it is welcomed that these figures have been subsequently index linked, resulting in a combined figure of £3,109 per dwelling, the industry as a whole has noted that build cost and the cost of materials has significantly increased in recent years. We recommend that these figures are updated (rather than being index linked) to ensure that the evidence is robust and therefore meets the tests of soundness.
We remain concerned, therefore, whether a 2% uplift represents a sufficient increase in build costs to allow for the delivery of CC/WE.
Notwithstanding this, whilst it is clearly desirable for new development to achieve the highest possible water efficiency, the mandatory national standard set out in the Building Regulations is 125 litres/person/day. NPPG Paragraph 56-014-20150327 states that where there is a clear local need, Local Plan policies can require a tighter optional requirement of 110 litres/person/day.
The Councils’ acknowledge that the 80 litres/person/day goes beyond what Local Authorities are currently able to require but considers there is a strong case for greater water efficiency in Greater Cambridge based upon strong evidence provided by the Integrated Water Management Study. This would make full use of water efficient fixtures and fittings, water reuse measures on site including surface water and rainwater harvesting, and grey water recycling. It acknowledges that the cost effectiveness improves with the scale of the project.
The Councils’ 80 litres/person/day target is not considered realistic. Instead, it is considered that the tighter optional requirement of 110 litres/person/day should be encouraged. It may be appropriate to set tighter standards for certain site allocations but a blanket requirement of 80 litres/person/day is not realistic.

The Greater Cambridgeshire Local Plan is supported by a Greater Cambridge Local Plan Strategic Spatial Options Assessment (November 2020).
The Assessment identifies that current over-abstraction of the Chalk aquifer is having a detrimental impact on environmental conditions. It acknowledges that none of the Councils’ growth strategies offer an opportunity to mitigate the existing detrimental impacts and there is no environmental capacity for additional development in the new Local Plan to be supplied with water by increased abstraction from the Chalk aquifer.
Major new water supply infrastructure is proposed and will be operational in mid-2030s, however, development in the interim will need to reduce abstraction through the implementation of ambitious targets for water efficiency. Such targets will be required to be addressed across all new developments.
It is understood that all development within Greater Cambridgeshire will need to adhere to such ambitious water efficiency targets and therefore there is no growth strategy that has a lesser water usage impact than another.
In so far as utilising recycling systems, the Assessment suggests that large sites are able to successfully use recycling to reduce demand for potable water. We disagree with this statement. Whilst retrofitting developments may be expensive, new development (regardless of scale) is able to adopt rainwater recycling systems. It is unclear why the statement specifically restricts water recycling usage to “large developments”. Land to the East Side of Cambridge Road, Melbourn, is able to adopt a rainwater recycling system if this is a requirement set by Local Policy.
The Assessment also identifies the potential for introducing flood management and SuDS schemes to deliver multifunctional benefits including biodiversity enhancements. Land to the East Side of Cambridge Road, Melbourn presents an opportunity for delivering a scheme which includes SuDS that provide multifunctional benefits including an opportunity to benefit and enhance designated wildlife sites.
Overall, however, the Assessment recommends that growth should be concentrated in new settlements or urban extensions that avoid high flood risk and have high standards for the design of flood risk management, water usage and re-use, and blue-green infrastructure.
This recommendation follows a Location Opportunities and Constraints Categorisation and Scoring which assesses and score each of the proposed growth strategies.
Minor Rural Centres (including Melbourn) are assessed as having a red rating for flood risk due to potential existing fluvial flood and surface water flood risk. Wastewater and Quality are assessed as amber, subject to local WRC capacity. The red flood risk rating is despite Paragraph 4.2.1 of the Assessment stating “flood risk does not differentiate between the growth scenarios”.
Land to the East Side of Cambridge Road, Melbourn is located within Flood Zone 1 with low risk of surface water flooding. In this regard the Site should be assessed as having a Green or Amber Flood Risk rating. In either instances, the Site should be given a total constraints score of -6. This score would result in the same overall scoring as the proposed recommended growth strategy of locating growth within new settlements or urban extensions. This amendment would also introduce the summary of “Good Opportunities”, thereby also improving the overall combined constraints and opportunities score for development within Minor Rural Centres and Group Villages.
It is therefore disputed as to why development within the Minor Rural Centres and Group Villages have been disregarded as an appropriate growth strategy if they are able to meet the ambitious water usage targets and implement water recycling systems.