To update your contact information with Northumbrian Water, it is typically necessary to log into your online account on their official website. Once you are logged in, you should be able to access your account settings, where you can find options to edit your contact details. This may include your address, phone number, or email address.
If you do not have an online account, or if you encounter any difficulties during the process, Northumbrian Water often provides additional guidance on their website. They may also have customer service representatives available to assist you with the update. It would be beneficial to visit their site for specific instructions or alternative options for updating your information, such as through phone or mail.