User-defined accounting methods (and rules discussed later) can be used to ensure that the accounting system is reconciled with the physical system; that is, the sum of the accounting releases is the same as the physical release and the sum of account storages is the same as the total object’s storage. RiverWare has no automatic checks to ensure that physical and paper water are reconciled. Each basin is unique and operates differently. As a result, it is the responsibility of the modeler to reconcile the two systems according to the legislation and operations of the basin. There are river basin that have legally decided that the accounting system can vary from the physical system on a daily basis and the total reconciliation happens on a monthly (or longer) timescale.

There are reconciliation categories on the aggregate diversion, reservoir, and water user objects. These categories can hold methods that set the Gain Loss slot, Slot Inflow slot, and/or accounting supplies. Reconciliation can also be accomplished using rules in a rulebased model. See Accounting With Rules for additional information on rules and accounting.