BEIJING -- A set of rules on household service industry management, which were created to reject improper practices in the booming sector, took effect in China Friday.

Issued by the Ministry of Commerce in December, the rules say household service agencies shall not default on workers' wages or overcharge employees in the name of management fees.

Household service agencies or workers shall enter into a written service contract with customers, or the agencies will face a fine up to 30,000 yuan ($4,800), according to the rules.

China has witnessed a booming household service sector in recent years, with the number of workers in this field rising to 15 million in 2011.