Section 18 Agreement Drainage

Our drainage design service provides valuable advice to clients on the most emotional and feasible solutions for drainage problems and options, including sustainable drainage systems (SuDS). This agreement allows the acceptance of a sewer or weir by a sewer company. An agreement is reached under Section 38, which provides a method for a highway built or to be built in order to be expanded at a public cost. In most cases, a highway open to the public will cover the drainage of the highway. (Highway drainage is defined in point 100 (9) of the Highways Act 1980). Existing drainage systems can also be proposed for adoption through a Section 102 (Water Industry Act 1991) agreement. The adoption of a drainage system by a section 104 agreement concerns a drainage system that drains private areas (such as roofs and driveways) as well as the drainage of highways (if both flow into the same pipeline system). The last authority to adopt is the Sewerage Undertaker. The cost of entering into such an agreement depends on the size of the development and drainage system required. The adoption of a drainage system by a Section 38 agreement provides for a drainage system that will drain only a supposed highway.

The drainage system takes only the flow of the supposed (or prospective) highways and no private drainage or drainage falls into the system. The last adoption authority is the local authority or the council. The cost of reaching such an agreement depends on the size of the development. Examples of our drainage know-how are the comprehensive detailed design of drainage layouts for clients such as major home builders, sustainable drainage concepts for significant employment developments, which include online and offline depreciation, clearing ponds, desaway soaks, swales, underground storage tanks and dry basins. Sanderson Associates provides developers with a comprehensive drainage design service that ranges from small private drainage systems to large wastewater and surface drainage systems for adoption with secondary south systems, so that developments can meet planning conditions for surface water flow requirements and wastewater discharge requirements. An agreement under Section 104 is reached and provides a method for a drainage system that has been built or is to be built, which can be maintained at the expense of the remediation authorities. Our drainage expertise is also monitored by our flood risk assessment services (see, which ensures that all recommended drainage or flood protection measures are the best rated and devoid of any design and adapt to such developments. Specific sections of Highway 1980 and the Water Industry Act 1991 authorize the adoption of a drainage system by a sewerage company (which will then be responsible for the future maintenance of the system). The usual course of drainage adoption for a new development is either through the agreement of Section 38 (Highways Act 1980) or by the Agreement Section 104 (Water Industry Act 1991) depending on who will take control of the drainage system.

An agreement under Section 106 allows for a new connection to an existing public sanitation system.