Frequently asked charges questions

Ofwat, our water industry regulator, carried out its latest price review in 2024. As part of that process, it looked at our business plan for 2025 to 2030 and set how much revenue we’re allowed to collect from customers each year. We’ve used their decision to shape our charges for the year ahead.

All water companies follow Ofwat’s charging rules when setting prices. Ofwat no longer approves each company’s charges individually. But these rules help make sure prices are fair, consistent, and clear for everyone. 

The bill figures you might see from Ofwat don’t include inflation and are based on an average across all customers. That means they won’t show the actual change to your own bill.

To give you a clearer idea, we use what’s called a 'typical' bill change. This includes inflation and the cross-subsidy that supports our social tariff. It also assumes you stay on the same tariff and use the same amount of water each year, making it a better guide to what you’re likely to see on your bill.

You might see reports in the media saying Thames Water bills are making a 0.4% increase. This is based on what's called an 'average' bill, and doesn’t always reflect what most customers actually pay. Instead, we usually talk about a 'typical' bill because it’s a better guide to what you’re likely to see on the bill you receive.

An average bill is worked out across all our customers - including those who receive support through our social tariff and pay less. Because of this, the average figure can appear lower.

Using a typical bill helps us explain price changes more clearly and honestly, so there are no surprises.

No, the appeal to the CMA will not affect our price changes for the year 2026-27.

Your new charges start on 1 April 2026. 

If you don’t have a water meter, your should receive your bill between February and March.

For customers with a meter, you’ll start seeing changes to your bill from April onwards.

If you pay by payment plan, your instalments may already have changed to reflect our new prices. These adjustments are based on how much water you’ve used so far and what we expect you’ll use over the next six months. We review your plan twice a year to help keep your payments accurate and avoid under or over‑charging.  

How you are billed depends on your tariff and the services you receive. You can learn more about how different customers are billed on our billing page.

For most households, water and wastewater bills increased by an average of 3.4% for 2026-27. This works out to around £2 more per month for most of our customers.

The impact on your bill may vary depending on the type of charges you pay:

• Metered customers - Your bill will change based on the amount of water you use
• Unmetered customers - Your charges are based on your property’s rateable value, so your bill may increase differently
• Assessed household customers - If you’re on our assessed tariff, your bill depends on the number of bedrooms in your home or, if you live alone

These differences help ensure your charges are as fair and reflective of your household’s needs as possible.

The percentage increase you see depends on the size of your bill and how it’s made up. For example, how the cost is split between water and wastewater services, and between fixed and variable charges.  

If you have a water meter and use little water, your bill will be mostly made up of fixed charges. And because fixed waste charges have decreased and fixed water charges have only risen slightly, your overall bill increase will be smaller. 

In contrast, a higher‑usage customer will pay for more units of water. And those unit prices have increased by around 10%, so their percentage increase will be higher. 

All our charges have been adjusted by the same percentage across all tariffs, ensuring the changes are fair and consistent.

No. Different parts of your bill change in different ways. For example, water charges have gone up, while waste charges have come down.

What is consistent is how we apply those changes within each type of charge:

• All water variable charges increase by the same percentage
• All waste variable and fixed charges change by the same percentage
• All retail fixed charges change by the same amount within each of our metered and unmeasured tariff types

This means that although not every part of the bill moves in the same direction, the changes are applied fairly and consistently.

Fixed charges help cover the basic costs of providing your water and wastewater services. These include:

• Drainage - collecting and treating rainwater that runs off your home and nearby roads
• Customer services - like billing, meter reading, and running our contact centre

For the 2026-27 period:

• Drainage service charges have decreased by 4.9%. This matches the same reduction applied to the unit rate for metered wastewater charges.
• Customer service charges have increased by 4.1%. This reflects the revenue allowance set by Ofwat for delivering these services. It also includes funding for the support we provide through our social tariffs, which help customers who are struggling to pay.

Our prices changed on 1 April, so your first metered bill of the year likely covered a mix of days across old and new charges.

Your next bill of that year would charge you at our updated prices only. This means that even if you’ve used a similar amount of water, the total cost would likely be higher.

Our new charges apply to all customers in our supply area and across our metered and unmetered tariffs.

We review our prices once a year, and this year our charges change on 1 April 2026. 

Ofwat sets the amount of revenue we’re allowed to collect from customers each year as part of its final determination for the 2025-2030 period. Our prices rise or fall each year in line with these allowed revenue changes.

We're investing a record £20 billion on improving water and wastewater services - more than double what we invested between 2020 and 2025.

This investment will help us: 

• Replace hundreds of miles of ageing and leaky pipes
• Install over one million smart meters to help customers track and reduce their water use
• Upgrade sewerage systems to help cut pollution and protect the environment

The investments we're making are part of our five-year plan.

We're committed to reducing the number of pollution incidents in our area by 30% by 2030.

To help us achieve this, we’ve developed a detailed Pollution incident reduction plan. This includes activities such as increased sewer cleaning and infrastructure investment.

We'll invest the money we collect from our customers into new infrastructure. This will help improve our services for your homes and the environment.

We haven’t paid any external dividends since 2017, and we’ve committed not to pay any before 2030.

Ofwat has ruled executive bonuses cannot be paid from money collected from customers. This is unless our performance meets expectations.

Keeping you informed about the investments we’re making is important to us. We share updates through our website, direct customer communications, and to the media.

The water sector is highly regulated, so you can be confident in the standards we follow. Ofwat, the Environment Agency, and the Drinking Water Inspectorate closely monitor all water companies in the UK to ensure services remain safe and reliable.

If you don't have a water meter, applying for one is quick and easy. Once you apply for a meter, we’ll arrange a survey to check whether a meter can be fitted at your home.

For many customers, having a meter can work out cheaper because you only pay for the water you use. Once you apply for a meter and it’s installed, you won’t be able to return to unmetered charges if you change your mind.

If you already have a meter, using water more efficiently - or fixing things like a leaking toilet - can help reduce your bill. Check out our water-saving tips for more ways you can make serious savings.

If you’re finding it hard to keep up with payments, we’re here to help. You can find out more about the financial support options available to you.

We’ve helped almost 500,000 customers manage their bills, and we’ll work with you to find the best options for you. You can view all the support schemes we offer on our financial support page.

Yes. You can set up a payment plan to spread the cost of your bill into regular instalments that suit you. You’ll be able to choose: 

• When your payments are taken
• How often you pay
• The payment method that works best for you

If you do not set up a payment plan, your bill will need to be paid in full within 14 days of receiving it. 

No. We’ll start charging you on a metered tariff from the date your meter is activated. Any unmetered charges up to that point will still need to be paid as normal.