The Clean Water Bill sits at the apex of a three-layer regulatory architecture for the English and Welsh water industry. The base layer is the Water Industry Act 1991, which remains the principal statute governing appointments, charges schemes, sewerage and water-supply duties, and the standard licence conditions on which Ofwat's economic regulation runs. The intermediate layer is the Environment Act 2021, which set statutory long-term targets through the Environmental Targets (Water) (England) Regulations 2023 and established the Office for Environmental Protection as the statutory governance body for environmental law.
The Water (Special Measures) Act 2025 is the interim layer the Clean Water Bill is intended to build on rather than replace. WSMA 2025 grafted new sections onto the Water Industry Act 1991: rules on remuneration and governance (s.35B–35D), pollution incident reduction plans with chief-executive personal liability (s.205A–205C), emergency-overflow reporting (s.141F–141G, prospective), and a financial-transparency duty (s.35E). It also modified the Regulatory Enforcement and Sanctions Act 2008 to lower the standard of proof for civil penalties against water companies and to create an automatic-penalty duty for specified offences.
The Clean Water Bill is expected to add a fourth layer — institutional reform. The Public Accounts Committee's July 2025 report confirms Defra's intention to introduce a single water regulator absorbing the water-related functions of Natural England, the Environment Agency, Ofwat and the Drinking Water Inspectorate 1. This will require primary legislation to restructure or repeal the founding Ofwat provisions in the WIA 1991 and to transfer functions from Schedule 7 to the Environment Act 1995 (which created the EA). The Cunliffe Independent Water Commission's 88 recommendations 2 provide the analytical scaffolding.
Cross-cutting, the regime engages the Environmental Permitting (England and Wales) Regulations 2016, under which most discharge consents and trade-effluent permits are issued and enforced. The October 2025 consultation on modernising environmental permitting 3 and the related exemptions-reform consultation 4 indicate that the permitting layer will be reformed in parallel.
What the regime cannot do without further legislation is end operator self-monitoring (asked in PQ 116558), require public-health task-force creation (PQ 116849), or restructure water-company ownership models — all matters likely to require express provision in the Bill.