Full details of the requirements are given in Part H3 Page 39 onwards.
[DLMURL]https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdfRainwater[/DLMURL] drainage H3. Requirement
(1) Adequate provision shall be made for rainwater to be
carried from the roof of the building.
(2) Paved areas around the building shall be so constructed as to be adequately drained.
(3) Rainwater from a system provided pursuant to sub- paragraphs (1) or (2) shall discharge to one of the following, listed in order of priority:
(a) an adequate soakaway or some other adequate infiltration system; or, where that is not reasonably practicable,
(b) a watercourse; or, where that is not reasonably practicable,
(c) a sewer.
Requirement H3(2) applies only to paved areas:
(a) which provide access to the building pursuant to requirement M1 (access and use of buildings other than dwellings), or requirement M2 (access to extensions to buildings other than dwellings), or requirement M4(1), (2) or (3) (access to and use of dwellings);
(b) which provide access to or from a place of storage pursuant to requirement H6(2) (solid waste storage); or
(c) in any passage giving access to the building, where this is intended to be used in common by the occupiers of one or more other buildings.
Requirement H3(3) does not apply to the gathering of rainwater for re-use.