Maintenance of the Novatron reverse osmosis is quite simple and cheap. Every six months you will need to change the three primary filters. You will receive a reminder by post for this 'service'. The cost is LM12 (28 euros), and it includes the delivery of the filters, changing them, checking up of the system and doing any adjustments or repairs that may be necessary, and testing your water.
Every 2-6 years, depending on the tap water quality, you will also need to change the membrane, which costs LM36 (83 euros). The technician will advice you during the periodic service if you need to change the membrane or not.
Regular services are very important to ensure best water quality, safety, will lengthen the membrane's lifetime and will also keep the lifetime guarantee valid.