The Building Regulations normally apply to new dwellings and to existing dwellings where a material alteration is being carried out. Where a service, such as a domestic septic tank, is being replaced, the requirements of the Building Regulations specific to the replacement apply. Part H of the Second Schedule to the Building Regulations, 1997 to 2010, provides for the disposal of foul and surface water. The related Technical Guidance Document TGD H, Drainage and Waste Water Disposal, provides guidance on how to achieve compliance with the requirements of Building Regulations in that regard. Given that the current regulations and related guidance already set out requirements in respect of septic tanks, there is no requirement to further amend Part H of the Building Regulations.