To make a web warehouse reflect the real web accurately, we should keep timeliness, freshness and consistency for the webviews. This paper fouses on one important part of webview maintenance – mutual consistency between webviews, which is formally named as multiple webview consistency (abbreviated as MVC). Although the same problem has been well studied in a traditional data warehouse, however, it has never been considered for a web warehouse. Since data sources in a web warehousing environment do not propagate base data changes to the information consumers, which is different from the case in the traditional data warehouses, it is not feasible to keep complete mutal consistency between the webviews in web warehouses. In this paper we introduce the Interrelated-MVC, a new term based on the features of the web environment. We show that it is enough to keep Interrelated-MVC in web warehouses. After that we present the algorithms which guarantee Interrelated-MVC and are scaleable to t...