You can use the same Pay2Wash account at all locations operated by one and the same company. However, if you want to use a location of another company, you will need to create a new Pay2Wash account with that company. You can (if desired) use the same email address and password, but it is and remains a completely separate account, so you will also need to upgrade this account separately. The reason for this is because when you top up, the money does not go to Pay2Wash, but directly to the company that operates the location.