Wcf service reference configure issue

Question

I am facing an issue while configuring wcf service. In two different system ,when same service is configured then two difference reference class is created. One is using namespace using System.Runtime.Serialization and other one is using System.Data. Both service and client projects are same and project properties everything i have checked ,all are same. Is there anything i am missing or any system configuration need to be done.Please advise.