Frequently asked charges questions
On this page we cover frequently asked questions relating to changes in our charges.
Why bills have gone up
Every day, we manage billions of litres of drinking water and wastewater. We must make investments to ensure we keep this essential service flowing. This allows us to continue to invest into our infrastructure and services.
How the prices were set
We go through how we set prices for billing our customers.
Who and how set the prices?
Our water industry regulator, Ofwat, finished their industry-wide price review for 2024. They reviewed our business plan for 2025 to 2030 and issued a final determination. It set the level of revenue we can recover from our customers. We used this as the basis for our charges over the upcoming charging year.
All water companies have to follow Ofwat’s charging rules when setting their prices. Ofwat no longer specifically approves the charges each water company sets.
Why did Ofwat give a lower percentage of bill rises than what you published?
The bill figures Ofwat published didn’t include the impact of inflation. It was an average of the price rises across all our customers. This included those who may move onto our social tariff and get a discount on their bill. These average bill increases didn’t reflect the actual increase to your bills.
We used a number that better reflects the price increase that you will see on your bills. This is known as a ‘typical’ bill increase. The increase includes inflation and a cross-subsidy that pays to fund social tariff. Typical bill increases assume that you’re staying on the same tariff from one year to the next. It also assumes you don't change the amount of water you use.
Will my bill be affected by appealing to Competition and Markets Authority (CMA)?
No, our price rises for 2025-26 will not change. The first year of the new five-year cycle 2025-2030 will carry on as planned. We've committed to achieving a lot in the first year.
When the increase starts and how much it is
We go through when the increase will start and how much it will be for each type of customer.
When will I get my first higher bill?
Your new charges started on 1 April 2025.
If you don’t have a water meter, your should have received your bill between February and March.
For water meter customers, you’ll start seeing changes to your next bill now.
If you pay by payment plan, your instalments may have already gone up based on our new prices. We usually check and adjust your payments. This is in line with how much water you’ve used and what we think you’ll use for the year ahead. We'll now reassess your plan every six months instead. This will make sure bills are as accurate as possible and that we’re not under or overcharging you.
How much has my bill increased by?
Bills for typical water and wastewater customers have increased by £17 per month. This is on average for 2025-26.
Your increase may be higher or lower depending on whether you pay metered or unmetered charges. If you're on our assessed household customers tariff, your bill will depend on the number of bedrooms in your property or if you live alone.
Why are the increases different depending on my tariff?
This is primarily because of the existing typical bill values for each tariff type. Our underlying unit rates for variable charges have increased by the same percentage. This applies across each tariff type. Our fixed charges have increased consistently across all tariff types.
Percentage increases for metered and assessed household customers is higher than for unmetered.
Have all parts of the bills (fixed charges and unit rates) increased in the same way?
No, different increases have been applied to different parts of the bill. Our unit rates for variable charges have generally increased by the same percentage. This applies across each tariff type. There are different rate increases for our water services and for wastewater services. Fixed charges have increased by a higher percentage than variable ‘unit rate’ charges.
The percentage increases also vary for different tariffs and service types. This is so that our charges are more consistent for all customers without a meter. Find out more in our statement of significant change
Do the new charges apply to all customers or just specific regions/plans?
The new charges apply to everyone in our supply area.
Will bills go up again soon? Will it be increased by the same amount?
We review our prices once a year. This year, our charges changed on 1 April 2025.
Ofwat set out in their Final Determination that prices are set to increase each year. We expect next year's price rise to be much lower and more in line with inflation.
What we'll spend the money on
We go through what we will spend the money on for the increase.
Where can I find out more about what you'll be spending the money on?
The new charges are part of our five-year business plan. It sets ambitious goals based on a record level of investment. You can view our five-year plan in progress.
What do you plan to do with the money?
Over the past few years, we’ve done everything we can to avoid increasing our prices. We'll invest the money to improve in the areas you've told us matter most to you.
- Keep safe, high-quality drinking water flowing with fewer interruptions
- Fix leaky pipes and the aging mains network to reduce wasted water
- Invest in upgrading our sewage works
- Reduce pollution incidents and storm overflows
- Ready the water network for population growth and climate change
The changes we're making are part of our five-year plan. This sets out our ambitious goals to invest in and improve services for you.
We also have a range of projects that are helping to transform our network and protect the planet.
Are you going to improve the health and water quality of our rivers?
We’ve set goals to reduce pollution in our five-year plan. The plan is still under review, but we’re currently aiming for a 30% drop in pollution incidents by 2030.
But no matter what happens, reducing pollution is a huge priority for us moving forward. We know we must do more to look after our rivers and streams. We’re determined to reduce pollution, storm overflows and blockages. You can view our five-year plan in progress.
Am I paying for the company's mismanagement, bonuses, debt, and dividends?
We haven't paid an external dividend since 2017, and we've committed to pay no external dividends before 2030. We're maximising investment to update our critical assets.
Ofwat has ruled executive bonuses cannot be paid from money collected from customers. This is unless our performance meets expectations.
Are customers paying the cost to improve Thames Water's financial position?
The £3 billion liquidity extension will not impact our proposed increase of bills. This includes the next five years.
The debt extension is an interim funding solution while we stabilise the business. Our aim is to deliver an investable and financeable business plan. This liquidity extension allows us to continue investing for the future.
How will I know that my money is being spent on the things you say?
It's important to us to keep you updated with the investments we’re making. We do this through our website, direct customer communications, and to the media. The water sector is also highly regulated. Ofwat and the Environment Agency monitor the activities of all water companies in the UK.
If water companies not meet their targets set by Ofwat, they face penalties. This can reduce the revenue that the water company can recover through bills.
Why are you asking for a referral of the Final Determination to the Competition and Markets Authority (CMA)?
The Thames Water Board has made the decision to refer Thame Water’s Final Determination to the CMA. This is to protect your interests as well as the best interests of the environment and our business operations.
The decision was not made lightly. We need to enter the next regulatory period on a stronger footing. This will help us support growth, improve your service, protect the environment, and adapt to climate change.
On 18 March 2025, the Thames Water Board and Ofwat agreed that Ofwat will defer making the reference for a period of up to 18 weeks.
Communicating the increase
We go through how we're communicating our price increase to customers.
I have received an email/letter from Thames Water about price changes. Is it legit?
We’re contacting customers by email or letter to make sure the following is communicated:
- Why our prices have changed
- Where that money will be invested
- How we can help if you’re worried about affording your bill
Support available
We go through what support is available for paying your bill and how you could save.
Can I switch to a cheaper tariff or plan to avoid a higher bill?
If you don’t have a water meter yet, using one could help you take better control of your bill. With a water meter, you can track and pay for exactly how much water you use.
In some cases, it can help you save money. This is dependent on if we're able to fit a meter at your property.
What support can you give me?
We’re helping around 450,000 customers pay their bills. We’re here to help find the best solution for you. You can view all the support schemes we offer on our financial support page.