Viterbo and Tarquinia issue water non-potability orders due to arsenic

An emergency has been declared in parts of Viterbo and Tarquinia due to arsenic levels in the drinking water exceeding legal limits. Following reports from Arpa Lazio, local authorities issued ordinances on October 3, 2026, prohibiting the consumption of tap water for food and drink in specific areas.

In Viterbo, the contamination affects ten streets supplied by the Rio Trai network, where arsenic levels reached 12 micrograms per liter, surpassing the 10 microgram limit. In Tarquinia, the ban covers the historic center and several localities, with levels recorded at 11 micrograms per liter. Water remains restricted to domestic hygiene and technological uses in these zones.

The water utility provider, Talete, has implemented emergency technical measures, including hydraulic maneuvers to optimize mixing and regulate flows. Preliminary monitoring suggests arsenic levels have begun to drop, with some readings falling to 6 or 6.5 micrograms per liter. Emergency water tankers have been deployed in affected areas, such as Montecchio street in Viterbo, to provide alternative supplies.

Local advocacy groups and organizations, including A. Ba. Co. Lazio and the committee ‘noncelabeviamo’, are demanding greater transparency and accountability from the municipal administration and Talete. They have called for a public city council meeting to clarify the cause of the emergency and are seeking to protect citizens from the additional costs associated with purchasing bottled water.