Abstract: In one example, there is provided a computer-implemented method for estimating, at a given time, a fluid flow state in a conduit of a property, comprising: obtaining historical data associated with at least one fluid flow state in the conduit, wherein the historical data comprises a history of the probability of the at least one fluid flow state in the conduit; obtaining a probability model for the at least one fluid flow state, wherein a probability for the at least one fluid flow state is a function of the historical data associated with the at least one fluid flow state; obtaining observed data associated with the property, the observed data including a measure representative of fluid flow in the conduit; and estimating a fluid flow state in the conduit of the property at the given time, based on the historical data associated with the at least one fluid flow state, the probability model and the observed data.