Yes. Even single dwellings can trigger nutrient neutrality rules if they are in a sensitive catchment. Local Planning Authorities (LPAs) are required to assess all developments that could increase nutrient loading, regardless of scale.

A NNAMS is the technical evidence used to show whether your development is nutrient neutral. This evidence feeds into the HRA process, which is the legal mechanism LPAs must follow before granting permission.

The NNAMS Navigator™ is our five-stage process for preparing nutrient neutrality assessments. It’s not a DIY guide, it’s the structured framework we follow to make sure every NNAMS is approached consistently, while tailoring the detail to the unique circumstances of each site.

Most assessments take 2–4 weeks once we have all required information. Timescales can vary depending on site complexity and LPA requirements.

Typically we need: site location and boundaries, proposed development layout and uses, existing land use and drainage information, and details of foul and surface water discharges. We will confirm the specifics with you at the start.

No consultant can guarantee approval, as each LPA has discretion. What we can do is reduce the risk of delay or refusal by following the NNAMS Navigator™ process, ensuring every assessment is clear, evidence-based, and aligned with policy.

The calculators provided by LPAs are based on Natural England’s guidance and are useful for preparing nutrient budgets. Many of them include an option to account for SuDS. However, they do not calculate the nutrient removal rates for you, those figures need to be derived separately and entered into the tool. Getting those numbers right is critical, as SuDS performance depends on design, location, and catchment context.

In addition, the calculators cannot provide advice on where mitigation needs to be located, or, in the case of wetlands, the hydrological characteristics required for them to function effectively. This is where assessments often fail: space may be allocated for mitigation without consideration of the water sources feeding it.

By following the NNAMS Navigator™ process, we ensure the nutrient budget is minimised appropriately and that mitigation strategies are credible, reducing the risk of over-reliance on credits or proposals that won’t satisfy the LPA or Natural England.

Yes, but only in limited circumstances, such as when phosphorus from a package treatment plant cannot reach a designated site. Proving this requires site-specific investigation and compliance with Natural England-approved criteria. If the exemption criteria cannot be met, a nutrient budget and mitigation will still be required.

No. Any water that enters the sewer is treated to the same standard at the sewage works, regardless of its quality when entering. Reducing phosphorus load upstream does not improve your site’s nutrient budget.

Yes. Although a formal market is still developing, it is possible to create mitigation schemes that benefit several developments and negotiate credit sales. However, Natural England must verify that nutrients are offset and that credits are legally tied to mitigation in perpetuity (80–120 years). Any transactions must be legally watertight.

Progress varies by region and is often slow, as LPAs need to secure land and implement mitigation schemes. Some areas now allow purchase of credits, but capacity remains limited. Private mitigation schemes continue to play an important role in providing timely solutions.

No. The most effective schemes minimise disruption to agriculture. Interceptor wetlands on riparian land and retrofit SuDS can be highly efficient, reducing nutrient loads by up to 50–80%. These options are often preferred by Natural England, as urban runoff is considered more polluting than agricultural runoff.

Water companies already have obligations to reduce nutrients under national regulation, but Natural England still requires new developments to demonstrate neutrality. Permits for treatment works vary based on location and housing demand. Developers remain responsible for demonstrating neutrality in planning applications.