The Water Industry Act 1991 is a piece of legislation in the United Kingdom that primarily aims to regulate the water supply and wastewater management industry. It lays out the framework for the privatization and regulation of water and sewerage services. The act addresses various aspects related to the provision, quality, and pricing of water services, as well as the environmental impact of wastewater discharge.

Key requirements outlined in the Water Industry Act 1991 include:

1. Regulation of Water Suppliers and Sewerage Undertakers: The act establishes regulations for companies operating as water suppliers (providing clean water) and sewerage undertakers (managing wastewater). These companies are required to obtain licenses and adhere to specified standards and obligations.
2. Quality and Availability of Services: The act sets standards for the quality of drinking water supplied to consumers. It also outlines provisions for ensuring a consistent and uninterrupted supply of clean water and efficient management of sewage systems.
3. Environmental Protection: The act addresses environmental concerns related to the discharge of wastewater into natural water bodies. It establishes regulations to control the treatment and disposal of sewage and other effluents to minimize their impact on the environment.
4. Consumer Protection: The act includes provisions to safeguard the interests of consumers, including mechanisms to address complaints, resolve disputes, and ensure fair pricing for water and sewerage services.
5. Pricing and Competition: The act promotes competition in the water industry by allowing other companies to enter the market and compete with existing suppliers. It also outlines principles for setting water and sewerage charges, aiming to balance the financial sustainability of the industry with reasonable consumer costs.
6. Enforcement and Regulation: The act provides authorities with the power to enforce its provisions and regulations, ensuring that water suppliers and sewerage undertakers comply with the established standards and obligations.

The Water Industry Act 1991 applies to water supply and sewerage services across England, Wales, and Scotland. It defines the roles and responsibilities of companies operating in this sector and establishes the legal framework within which they must operate. The act's overarching goal is to ensure the efficient provision of high-quality water and wastewater services while safeguarding the environment and consumer interests.

The Water Industry Act 1991 sets forth specific evidence requirements to ensure the proper regulation and functioning of water supply and sewerage services in the United Kingdom. These evidence requirements are essential to ensure compliance with the act's provisions and to maintain the quality, safety, and sustainability of water services. Some key evidence requirements under the act include:

1. License Applications: Companies seeking to become licensed water suppliers or sewerage undertakers must provide evidence of their financial and technical capabilities to operate effectively in the industry. This may include demonstrating financial stability, technical expertise, and operational plans.
2. Quality of Water Supply: The act requires evidence that water suppliers are meeting specified quality standards for the drinking water they provide to consumers. This could involve regular testing and analysis of water samples to ensure that it meets health and safety guidelines.
3. Efficient Sewerage Management: Sewerage undertakers are expected to provide evidence of efficient management of wastewater systems, including evidence of proper treatment and disposal of sewage and effluents. This may involve maintaining records of treatment processes and monitoring the impact of wastewater discharge on the environment.
4. Environmental Impact Assessments: When proposing changes or developments that might impact water resources or the environment, evidence in the form of environmental impact assessments is often required. These assessments help to evaluate potential risks and provide measures to mitigate negative effects.
5. Consumer Complaints and Disputes: Water companies must maintain records of consumer complaints and dispute resolutions. Evidence of effective mechanisms to address customer concerns ensures that consumer rights are protected.
6. Pricing and Cost Structure: Evidence related to pricing structures and cost calculations is necessary to demonstrate that charges for water and sewerage services are fair and transparent. This helps ensure that consumers are not subjected to unreasonable or unjustified costs.
7. Compliance with Regulations: Companies operating in the water industry must provide evidence of compliance with various regulations outlined in the act. This could include evidence of adherence to environmental standards, health and safety regulations, and other legal requirements.
8. Environmental Monitoring: Evidence of regular environmental monitoring, such as water quality testing, pollution levels, and ecological impact assessments, is crucial to ensure that the industry's activities do not harm the environment.
9. Technical Capacity and Infrastructure: Water suppliers and sewerage undertakers must provide evidence of their technical capacity and infrastructure to reliably deliver water and manage wastewater. This could involve demonstrating the maintenance and functionality of treatment plants, distribution networks, and other essential facilities.

These evidence requirements collectively contribute to maintaining the integrity and effectiveness of water supply and sewerage services, promoting environmental sustainability, safeguarding consumer interests, and ensuring the industry's compliance with legal and regulatory standards as outlined in the Water Industry Act 1991.