The cost of storing the electronic voting machinery was €489,000 in 2007, compared to €706,000 in 2006.
The Public Accounts Committee has heard that the saving comes after the Department moved 60% of the machines to a centralised storage area in Gormanstown.
In response to a question from Committee Chairman Bernard Allen, Department of Environment Secretary General Geraldine Tallon said there were 'relationships' between some returning officers and owners of premises where the machines were stored.
She said it was a minority of cases where the returning officers had an interest in the storage premises.
In Dublin one such storage facility was on an annual lease, and in Cork city another was on a 10-year lease.
Ms Tallon said that the equipment in both cases had now been moved to the Department's facility in Gormanstown.
The Public Accounts Committee also heard that the Mahon Tribunal has cost the State €72.7m since it started.
In 2006 the tribunal of inquiry cost €16.1m, and €10.4m in 2007.
In response to a question from Fianna Fáil Deputy Sean Fleming, Ms Tallon said that costs are monitored on a regular basis.
Third party costs amounted to €8m, operational costs were between €9-€10m each year, and the cost of legal teams were over €40m at this stage.
In relation to contingent liability and future costs, Geraldine Tallon said it was very difficult to estimate.
She said no legal costs have been awarded since 2002 and she did not have a detailed list of costs to be yet determined.