Commercial premises

Commercial premises are non-residential buildings used for business purposes, including offices, shops, restaurants, warehouses and industrial units. Across Greater London, commercial premises are concentrated in central business districts (Westminster, Camden), high streets and industrial estates in Brent, Ealing and Enfield. Drainage characteristics vary considerably by use class, with offices having broadly domestic-scale loads while restaurants, kitchens and industrial users may discharge trade effluent that requires a consent from Thames Water under the Water Industry Act 1991. Common issues include grease blockages from food preparation, oil and silt blockages from forecourts, and unauthorised connections from changes of use. Building managers should hold accurate as-built drainage records, arrange periodic CCTV surveys and ensure trade effluent consents are in place and complied with to avoid enforcement action.