The Quality of Service Code for the natural gas sector (RQS) is aimed to establish service quality standards of a technical and commercial nature with which the services provided in the National System of Natural Gas must comply.
The RQS defines the rules for the evaluation and description of the quality of the service related to the supply of natural gas, and applies to clients, suppliers and sector infrastructure operators (distribution network, transmission network, underground storage and LNG reception, storage and re-gasification terminal).
The RQS also establishes the rules which are aimed to guarantee a minimum level of quality in the service provided to clients, namely through provisions related to:
- Competences, responsibilities and obligations of the different operators and agents involved.
- Technical and commercial service quality indicators and standards.
- Compensation to be paid to clients by companies when the defined quality standards are not met, and also the compensation to be paid by clients to companies for not complying with their obligations.
- Clients with special needs and priority clients.
With the objective of monitoring and checking the levels of the quality of service provided, the RQS focuses on the technical and the commercial aspects.
The technical aspect relates to issues on the supply of natural gas such as:
- Continuity of supply.
- Characteristics of the natural gas supplied and supply conditions.
On the other hand, the commercial aspect relates to the relationship between the distribution network operators or suppliers, including the last resort suppliers and the clients (for example: customer service, information and complaints).
The Quality of Service Code was approved by 
Regulation n.º 139-A/2013, published in Diário da República, 2.ª série, on the 16th of April, after the 42nd Public Consultation from ERSE.