Demonstrating compliance with the National Standards for SuDS

It is expected that your drainage statement will include a short section which clearly refers to the NSfS and acknowledges full compliance with the standards, or where any departures from them are requested to be approved. However, it should be noted that such departures are rarely entertained by engineers. Each of the 7 standards should be referenced with a short statement which also directs the reader to where supporting evidence can be found.

For example:

“Standard 1: Runoff Destination 

The SuDS for the site fully comply with this standard. No departure from the National Standards for SuDS is requested. The design follows the hierarchy for sustainable drainage by prioritising water reuse and then discharging to a watercourse within the site, as infiltration is not viable. Further information demonstrating compliance can be found in sections xxx of this report, and in appendices xxx (which include ground investigations, topographical survey and catchment plans as appropriate).”

Agreeing a departure from the National Standards for SuDS

Many elements of the NSfS use the language of 'shall'. The guidance is clear that this indicates a performance or method-based requirement of the standards which can only be varied through a departure agreed with the approving body.

When a planning application is made, the approving body is the decision maker; the Local Planning Authority (LPA). In practice this will be the planning officer acting under delegated authority, or the planning committee.

If an applicant or a designer wishes to agree a departure from the NSfS, then it suggested that this is done via the pre-application advice process. This reduces the likelihood of delays in decision making.

Our engineers and the Lead Local Flood Authority act as consultees, assessing SuDS designs. Their role is to assess the design against the national guidance that the NPPG points them to. This assessment is then offered to the LPA to inform their decision. The consultees are not decision makers and nor do they consider the other planning merits of a scheme beyond the discipline which they are consulted on. It is therefore inappropriate for the consultee to agree to a departure from the NSfS.

Where requested by the LPA, a consultee may offer advice as to the impact of a departure, if agreed.

When a departure has been agreed, this will be acknowledged within the officer report attached to the planning decision notice. The officer will acknowledge advice that demonstrates non-compliance with the NSfS and explain why that departure is accepted in their weighted balanced decision.