The guaranteed standards scheme summary guidance

Water and wastewater customers (‘customers’) are entitled to guaranteed minimum standards of service (GSS), as set out by Secretary of State and the Welsh Ministers. Ofwat publishes guidance that summarises these standards and conditions.

Click below to find out more about:

• About the guidance
• Summary guidance and other key documents
• Customers’ rights
• GSS and the business retail market
• Further information

Page last updated: 6 February 2026

About the guidance

This guidance is not intended to be a substitute for the Water Supply and Sewerage Services (Customer Service Standards) Regulations 2008 (otherwise known as ‘the GSS Regulations’). Each water and sewerage company or retailer is responsible for ensuring that it understands and correctly interprets its statutory obligations under the GSS Regulations.

In this guidance, a customer is someone who receives water or wastewater services from a company that holds an appointment as a water or sewerage undertaker (a ‘water or sewerage company’) or from a company that holds a water supply licence or a sewerage licence (a ‘retailer’). Where a company fails to meet a standard, it is required to make a specified payment to the customer affected under the Guaranteed Standards Scheme (‘GSS’). We monitor the scheme and recommend changes, if necessary, to Government.

Summary guidance and other key documents

Customers’ rights

The GSS Regulations apply to all customers.

If a company fails to meet any of the guaranteed standards, customers are entitled to a payment. Details of the payments due are set out in a table below.

The company must make the required payment within ten working days of the payment becoming due for failures around missed appointments, complaints, account queries and requests around payment arrangements and within 20 working days for all other failures. In the case of external sewer flooding, the company must make the payment to the customer before the end of the period of 20 working days beginning with the day on which the customer makes a claim

If the company fails to do this and the customer makes a claim for an additional penalty payment within three months of the required payment becoming due, the company must make the additional penalty payment.

Some companies operate schemes that go further than required by the GSS Regulations. For example, where a reply to a complaint letter is required in ten working days under the GSS Regulations, the company may raise this standard to five working days. In other cases, a higher amount may be paid than the minimum amount set out in the GSS Regulations.

Each water and sewerage company must inform billed customers of their rights under the GSS Regulations every year.

The standards prescribed under the GSS Regulations which companies must meet are set out in this document.

GSS and the business retail market

On 1 April 2017 amendments to the GSS Regulations came into force (The Water Supply and Sewerage Services (Customer Service Standards) (Amendment) Regulations 2017). This was to give effect, in England, to the extension of the retail market for water and wastewater services for businesses, charities and public sector organisations (‘business customers’).

The GSS Regulations (as amended) made provision relating to supplies to business customers by water supply and sewerage licensees (retailers) using the networks of water or sewerage companies that operate wholly or mainly in England. In such circumstances:

• the retailer is responsible for making GSS payments to its business customers in all instances; and
• the responsibility for funding payments to business customers is shared betweentheretailerandthewholesaler,andwillbemadebythepartythatis at fault for the GSS Regulation failure.

A wholesaler is a water or sewerage company that has exited the business retail market and provides wholesale services to retailers.

Payments under the GSS scheme to customers are distinct and separate to charges levied under the Market Performance Framework set out in the Market Codes to drive improved performance in the Business Retail Market

Further information

Under no circumstances will we be bound to interpret the GSS Regulations in accordance with these summaries. When considering regulatory decisions, in particular in determining disputes, we will consider the original text of the GSS Regulations as well as the facts as they arise.

If you want to know more about the GSS, your local water or sewerage company can provide a description of GSS (and any company-specific enhancements) to you on request.

You can also:

• visit our website at ofwat.gov.uk
• for complaints about GSS, contact the Consumer Council for Water (CCW) at ccw.org.uk