Newport Beach failed to meet water-reduction mandates in June and is facing increased scrutiny from state water officials.
Newport was ordered to cut 28% of its water use from June to February compared with those months in 2013, but only managed 21%, according the State Water Resources Control Board.
"It's a tall order, but we have to do it," said George Murdoch, the city's general manager for utilities. "We have to do more."
The violation will require the city, which serves 66,219 customers, to detail steps it is taking to decrease water use.
Californians overall cut their June water use by more than 27% — exceeding Gov. Jerry Brown's emergency orders in April to reduce by 25%.
The data show that in June, Newport Beach used 108 gallons of water per person each day, which places it above the 97.7 gallon per-person statewide average.
The City Council in May moved to Level 3 conservation, meaning violators can face fines of up to $500 for not sharply reducing water use.
Under the plan, ratepayers have had to restrict their water use in each billing period to 75% of their average use for that period in the past three years. Customers are barred from watering landscaping between 9 a.m. and 5 p.m. daily and from watering for up to two days after a rainfall.
The city also has turned off sprinklers watering landscaping on street medians.
Newport this summer is adding four code enforcement officers to make sure customers are following the water-conservation plan as well as ramping up a communication campaign by adding more signs citywide and placing door hangers on every house.
While they were previously billed every two months, ratepayers will receive monthly bills beginning in August so they can more effectively track their use.
The city may create a Smartphone application that would allow ratepayers to look at how much water they're using compared with previous months.
"We have customers that want to cut back but don't know how they're doing," Murdoch said. "These measures will help with that."
Another local water district also missed its goal. The state ordered Irvine Ranch Water District to cut 16% from June to February compared with 2013, but use dropped only 12% in June.
Irvine Ranch ratepayers used 70 gallons of water per person per day, below the 97.7 per-person average.
Irvine Ranch pointed to a 7% population increase in its service area since 2013 to explain its conservation level.
The district serves parts of Newport, Irvine and unincorporated areas.
"The officially reported reduction of 12% from June 2013 does not take into account population growth and the related effects on potable water production," a spokesperson told the Los Angeles Times.
Based on the district's calculations adjusted for population growth, the Irvine Ranch Water District reduced its water use by 22%, the agency told The Times.
Orange County Coastkeeper, an environmental group, is pushing non-complying agencies to meet state standards.
"There is no room for excuses," said Executive Director Garry Brown.
One area agency exceeded its goal. Mesa Water District, which serves 108,000 customers in Costa Mesa and portions of Newport, decreased use 26% — exceeding its 20% mandate.