Thames Water

Water company. Products & services: Water & sewerage.

Updated: 2 August 2026

Company Overview

Industry: Water supply and wastewater (sewerage) services
Parent company: Kemble Water group (via Thames Water Utilities Holdings Limited); creditor-led recapitalisation under way as of August 2026
Regulator: Ofwat (economic regulator); Environment Agency and Drinking Water Inspectorate (environmental and water-quality regulators)
Ombudsman: No statutory water ombudsman: Consumer Council for Water (CCW) reviews complaints; the Dispute Resolution Ombudsman provides binding ADR
Customers: Around 16 million people across London and the Thames Valley
Founded: 1989 (water privatisation; company incorporated 1 April 1989)
Legal entity: Thames Water Utilities Limited (Companies House no. 02366661)

What customers complain about

Customers complaining to Thames Water most often raise billing and account issues, which dominate water-sector complaints, alongside concerns about environmental performance (sewage and pollution), metered bills, affordability and service. CCW's household complaints reporting rated Thames Water the worst performer in England and Wales in 2023-24, at 139 written complaints per 10,000 customers, and 'poor' on both complaint volume and handling; in 2024-25 it showed some improvement but remained among the poorest performers. Thames Water is regulated by Ofwat, which fined it a record £122.7m in May 2025 (£104.5m for wastewater failures and £18.2m over unjustified dividends). The Environment Agency has separately prosecuted it, including a £3.3m fine in 2023 for a 2017 sewage pollution incident. There is no statutory water ombudsman: complain to Thames Water, then CCW can take up the complaint for free, and the Dispute Resolution Ombudsman gives a binding decision after deadlock. Guaranteed Standards Scheme payments apply for certain service failures.

Complaint categories

1
Billing and account issues
Disputes over bills, charges, metered bills and account handling are the single biggest source of water complaints, and Thames Water is the largest biller.
CCW reports billing as the top complaint category across the water sector, accounting for around two-thirds of complaints made to companies (63%) and to CCW (66%) in 2024-25.
2
Environmental performance (sewage and pollution)
Complaints about sewage spills and environmental performance rose sharply, an area where Thames Water has faced repeated regulatory action.
CCW attributed a near-third rise in complaints escalated to it in 2023-24 partly to concern over water companies' environmental performance; Ofwat's £104.5m wastewater penalty against Thames Water concerns storm-overflow spills.
3
Metered bills and affordability
Concern over meters and the affordability of rising bills features heavily in escalated complaints.
CCW cited metered bills as a driver of escalated complaints in 2023-24, and reported affordability complaints up 110% and bill-increase complaints up 138% in 2024-25.
4
Complaint handling and delays
How Thames Water handles and responds to complaints is itself a recurring problem.
CCW rated Thames Water 'poor' on complaint handling in both 2023-24 and 2024-25.

Latest statistics

139(the worst of any company in England and Wales)Written complaints received per 10,000 customers2023-24 (CCW household complaints report, published Oct 2024)

Statistics come from CCW's annual household complaints reporting, which compares every water and sewerage company. Figures are period-specific: CCW's 2024 report covers 2023-24 and its 2025 report covers 2024-25. Water companies have no Citizens Advice star rating and no Financial/Energy Ombudsman, so none is shown.

Contact methods

Complaint journey

1
Complain to Thames Water
Contact the right complaints team for your issue.
Typical responseImmediate
What happens
Contact Thames Water using the line for your issue: water and wastewater complaints on 0800 316 9800 (24/7), or bill and account complaints on 0800 980 8800 (Mon-Fri 8am-8pm, Sat 8am-6pm). You can also write to Thames Water, PO Box 436, Swindon, SN38 1TU. Give your name, address, account number, phone number and the best time to contact you.
2
Get a reply within 10 working days
Thames Water investigates and responds.
Typical response10 working days
What happens
Under the Guaranteed Standards Scheme, Thames Water should be in touch by phone or letter within 10 working days of receiving your complaint. If it fails to send a full reply in time, you are entitled to an automatic £40 GSS payment in England (£20 in Wales).
3
Final response or deadlock
You reach the end of Thames Water's procedure.
Typical responseVaries
What happens
Work through Thames Water's complaint stages until it issues a final response or you reach deadlock. Keep every reference number and letter, which you will need to escalate.
4
Ask CCW to take it up
The consumer body can help for free.
Typical response8 weeks
What happens
If you remain unhappy, or your complaint is unresolved after 8 weeks, contact the Consumer Council for Water (CCW) on 0300 034 2222. CCW is the free, independent statutory consumer body for water; it can advise you and take up the complaint with Thames Water. CCW is not a regulator and does not fine the company.
5
Refer to the Dispute Resolution Ombudsman
Independent adjudication once deadlocked.
Typical response20 working days
What happens
If the complaint stays deadlocked and CCW confirms you can apply, you can refer it free to the Dispute Resolution Ombudsman, the water sector's alternative dispute resolution provider appointed via Water UK in 2026. Its decision is binding on Thames Water if you accept it; if you reject it you keep your right to go to court.

Response times

Thames Water says it will be in touch by phone or letter within 10 working days of receiving your complaint. This mirrors the Guaranteed Standards Scheme (GSS), under which a water company must send a full reply to a written complaint or account query within 10 working days and owes an automatic £40 in England (£20 in Wales) if it misses that. Other GSS standards carry fixed payments too: £50 for a missed or wrongly cancelled appointment in England, and £10 for each day (or part day) that the water supply is interrupted, up to the previous year's average bill. If your complaint is not resolved to your satisfaction, or remains unresolved after 8 weeks, you can ask CCW to take it up for free; a deadlocked complaint can then go to the Dispute Resolution Ombudsman for a binding decision.

If your complaint isn’t resolved

If Thames Water can’t put things right, you can escalate — free of charge — to an independent body:

Consumer Council for Water

Recent news

28 May 2025
Ofwat fined Thames Water a record £122.7m following two investigations: £104.5m for wastewater failures (three-quarters of its storm overflows found to be spilling routinely rather than in exceptional circumstances) and £18.2m for breaking dividend rules, after a £131.3m dividend paid in March 2024 was judged undeserved. Ofwat CEO David Black said Thames Water 'has let down its customers and failed to protect the environment'; the penalty is borne by the company and shareholders, not customers.
Read more
3 June 2025
US private equity firm KKR withdrew from a planned c.£4bn equity rescue of Thames Water and its preferred-bidder status lapsed, deepening the company's financial crisis and leaving a creditor-led recapitalisation as the main alternative to special administration.
Read more
21 July 2026
The London & Valley Water consortium of Thames Water's senior creditors confirmed it remained in active discussions with regulators over a recapitalisation involving around £10bn of new capital (including new equity), positioning it as a market-led alternative to the Government's special administration regime, which had not been triggered.
Read more

Earlier cases

4 July 2023
Historic: Thames Water was fined £3.3m after a 2017 incident in which millions of litres of undiluted sewage were discharged into the Gatwick Stream and River Mole, killing more than 1,400 fish. The judge found Thames Water had made a 'deliberate attempt' to mislead the Environment Agency. The Environment Agency said Thames Water had by then paid £35.7m for pollution incidents between 2017 and 2023.
Read more

Know your rights

Guaranteed Standards Scheme (Water Supply and Sewerage Services (Customer Service Standards) Regulations)
Sets minimum service standards for water companies with fixed automatic compensation, for example £40 in England if Thames Water does not fully reply to a written complaint within 10 working days, £50 for a missed appointment, and £10 for each day the supply is interrupted. You can claim within three months if payment is not made automatically. This is general information, not legal advice.
Consumer Rights Act 2015
Water and sewerage supply is a service that must be provided with reasonable care and skill; where it falls short you may be able to seek a repeat performance or a price reduction. Not legal advice.
Water Industry Act 1991
Governs water companies' duties and the powers of Ofwat and the Environment Agency, including standards of service and the regime under which penalties and the special administration process operate. Not legal advice.

Frequently asked questions

How do I make a complaint to Thames Water?

Call the line for your issue: 0800 316 9800 (water and wastewater, 24/7) or 0800 980 8800 (bill and account, Mon-Fri 8am-8pm, Sat 8am-6pm), or write to Thames Water, PO Box 436, Swindon, SN38 1TU. Give your name, address, account number and phone number. Thames Water should reply within 10 working days.

Is there a water ombudsman for Thames Water complaints?

There is no statutory water ombudsman. If Thames Water cannot resolve your complaint, the Consumer Council for Water (CCW) can take it up for free, and a deadlocked complaint can go to the Dispute Resolution Ombudsman for a binding decision.

When can I escalate a Thames Water complaint to CCW and the Dispute Resolution Ombudsman?

Contact CCW (0300 034 2222) once you remain unhappy or your complaint is unresolved after 8 weeks. If it is deadlocked and CCW confirms you can apply, refer it free to the Dispute Resolution Ombudsman; its decision is binding on Thames Water if you accept it.

Will Thames Water pay me compensation if it misses a standard?

Under the Guaranteed Standards Scheme you are entitled to fixed automatic payments, for example £40 in England if Thames Water does not fully reply to a complaint within 10 working days, £50 for a missed appointment, and £10 per day of supply interruption. If it is not paid automatically, claim within three months.

Has Thames Water been penalised by its regulators?

Yes. In May 2025 Ofwat imposed a record £122.7m penalty (£104.5m for wastewater failures and £18.2m over dividends), and the Environment Agency fined Thames Water £3.3m in 2023 for a 2017 sewage pollution incident. These penalties fall on the company and shareholders, not customers, and do not resolve individual complaints.

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