Each supply belongs to a specific reading route and has the same reading and billing periodicity. In general, reading routes for low voltage supplies are every two months, although there are sometimes the following exceptions: Supplies with a maximeter installed are read and billed monthly. Supplies with high consumption levels that, with the agreement of both parties, are read and billed monthly. Supplies in rural environments which are geographically remote and have low consumption levels are read and billed every four months. Supplies in rural environments which are difficult to access at certain times of the year due to the weather are read and billed every four months. On occasions the reading and billing period may be altered for a number of reasons. These include: Signing up to the service during a reading and billing period. Change to contract mode. Removal of meter due to renovations being carried out on the estate or house, or problems with the measuring equipment.