Californians’ water conservation slipped for the third consecutive month in August, prompting new alarm from regulators about whether relaxed water restrictions may be causing residents to revert to old habits as the state enters its sixth year of severe drought.

The trend raises new questions about Californians’ willingness to continue austere conservation after spending the last two years dramatically reducing their water use by ripping out lawns, installing water-sipping appliances and shortening their showers.