A
Abuse of dominance
Conduct by a company holding a dominant market position that harms competition or consumers, prohibited under Chapter II of the Competition Act 1998 and Article 102 TFEU.
Access pricing
The charges set by an incumbent water company for allowing a new entrant to use its network infrastructure (common carriage). Central to the Albion Water litigation.
AMP (Asset Management Period)
The five-year regulatory cycle used by Ofwat for setting water company price controls and investment programmes. Currently AMP8 (2025–2030).
Audi alteram partem
Latin: “hear the other side.” A principle of natural justice requiring that all parties be given an opportunity to present their case before a decision is made.
B
BAILII
British and Irish Legal Information Institute. A free online database of UK and Irish case law, legislation, and legal materials. Primary source for many cases in this wiki.
Bathing Water Directive
EU directive (retained in UK law) setting quality standards for designated bathing waters. Relevant to EA monitoring and water company discharge obligations.
C
CAT (Competition Appeal Tribunal)
A specialist UK tribunal that hears appeals and claims relating to competition law, including abuse of dominance, merger reviews, and collective consumer proceedings.
CON29DW
The standard drainage and water search form used in property conveyancing in England and Wales. At issue in Surrey Searches v Northumbrian Water.
Collective proceedings
A form of group litigation available in the CAT under the Consumer Rights Act 2015, allowing a representative to bring a claim on behalf of a defined class of consumers.
Common carriage
The use of an incumbent water company’s network by a third-party supplier to transport water to end customers. Central to competition reform in the water sector.
CSO (Combined Sewer Overflow)
An overflow structure on a combined sewer that discharges a mixture of sewage and rainwater into a watercourse during heavy rainfall. Also known as a storm overflow.
D
Defra
Department for Environment, Food and Rural Affairs. The UK government department responsible for water policy, environmental regulation, and the strategic policy statement to Ofwat.
Duty of care
A legal obligation to take reasonable care to avoid causing harm to others. Established in Donoghue v Stevenson [1932] and foundational to negligence law.
DWI (Drinking Water Inspectorate)
The independent regulator of drinking water quality in England and Wales, responsible for ensuring water companies comply with water quality standards.
E
EA (Environment Agency)
The environmental regulator for England, responsible for water quality, flood risk, and environmental permitting. Prosecutes water companies for pollution offences.
EDM (Event Duration Monitoring)
Monitoring equipment on storm overflows that records when and for how long discharges occur. Data is published annually under Environment Act 2021 requirements.
EIR (Environmental Information Regulations 2004)
UK regulations implementing the Aarhus Convention, providing a right of access to environmental information held by public authorities and certain private bodies.
Environment Act 2021
UK legislation establishing new environmental governance, including duties on water companies to report storm overflow discharges and reduce their environmental impact.
H
HRA (Human Rights Act 1998)
UK legislation incorporating the European Convention on Human Rights into domestic law. Article 8 (right to private and family life) is relevant to sewer flooding cases.
J
Judicial review
A court procedure for challenging the lawfulness of decisions made by public bodies and regulators. The court examines whether the decision was lawful, rational, and procedurally fair.
M
Margin squeeze
A form of abuse of dominance where an incumbent sets access prices so high that a competitor cannot profitably serve customers, even if the competitor is equally efficient.
N
Nemo judex in causa sua
Latin: “no one should be a judge in their own cause.” A principle of natural justice requiring impartiality in decision-making.
Nuisance
A tort involving unreasonable interference with the use or enjoyment of land. Private nuisance claims are central to water pollution and sewer flooding cases.
O
Ofwat
The Water Services Regulation Authority. The economic regulator of the water and sewerage sectors in England and Wales, responsible for setting price controls and monitoring company performance.
Outfall
The point at which a sewer or drain discharges into a watercourse, the sea, or other receiving water. The infrastructure at the centre of many sewage discharge cases.
P
Permit (environmental)
An authorisation issued by the Environment Agency under the Environmental Permitting Regulations allowing a water company to discharge treated or untreated effluent, subject to conditions.
Price review
Ofwat’s periodic process for setting the allowed revenues and performance targets for water companies. PR24 covers the period 2025–2030 (AMP8).
S
Section 94 (WIA 1991)
The statutory duty on sewerage undertakers to provide, improve, and extend a system of public sewers to effectually drain their area. Central to Marcic v Thames Water.
Section 141 (WIA 1991)
Provision of the Water Industry Act dealing with water company powers in relation to water fittings and supplies. At issue in Boots v Severn Trent.
Stare decisis
Latin: “to stand by things decided.” The doctrine of judicial precedent requiring courts to follow decisions of higher courts in the same hierarchy.
Storm overflow
A structure on a sewer network designed to discharge excess flow during heavy rainfall to prevent sewer flooding. Subject to increasing regulatory and legal scrutiny.
T
Trespass
A tort involving direct, unauthorised interference with another’s land or property. Relevant to cases involving discharges onto third-party land or watercourses.
U
UKSC (UK Supreme Court)
The highest court in the United Kingdom for civil and criminal appeals. Replaced the Appellate Committee of the House of Lords in 2009.
W
Water Industry Act 1991 (WIA 1991)
The primary legislation governing the water and sewerage industry in England and Wales. Establishes the duties, powers, and regulatory framework for water companies.
Water (Special Measures) Act 2025
Recent legislation strengthening regulatory powers over water companies, including provisions for enhanced governance, accountability, and environmental performance requirements.
Wayleave
A right granted to a utility company to install and maintain equipment on private land, typically in exchange for compensation. Relevant to pipe-laying disputes.
WRMP (Water Resources Management Plan)
A statutory plan produced by each water company setting out how it will manage and develop water resources over a 25-year planning horizon.