Go ahead and drown your petunias every day of the year. The city of San Diego won’t like it, but it won’t stop you.

Unlike most water sellers in the county, San Diego doesn’t limit the number of days per week that residents can irrigate their lawns and gardens. An environmental group is calling foul, accusing the city of ignoring new statewide restrictions on water use amid a worsening drought.

“San Diego needs to get on board,” said Matt O’Malley, legal and policy director for San Diego Coastkeeper, which wants the city to outlaw frequent irrigating. “They need to put the rules in place and enforce them.”

The California water board told me it plans to look into the dispute, and the city is sticking to its guns. The city says its rules are just fine, despite a summer in which San Diegans failed to trim back their water use over last year in June and July.

At issue: What did the California water board mean in July when it told the hundreds of water agencies around the state to start cracking down on irrigation with mandatory rules?

The city’s interpretation is this: We can do what we want regarding irrigation rules as long as they’re mandatory. And besides, we already had mandatory irrigation rules in place, and all that talk at the state level about a 20-percent reduction in water use isn’t in any law. There’s “no one-size-fits-all” solution, argued city water official Halla Razak in an Aug. 12 letter to Coastkeeper.

With some exceptions, such as when irrigation is required by a permit, the city forbids watering after between 10 a.m. and 6 p.m. from June to October and from 10 a.m. to 4 p.m. the rest of the year. Users must fix leaks and not allow runoff due to excessive watering or leaks. The city “strongly recommends” that people irrigate just three days a week, but it doesn’t require them to do so.

City spokesman Craig Gustafson said the city’s water rules are actually stricter than those required by the water board. And that’s not all, said Razak, the city’s director of public utilities, in the letter to Coastkeeper. The state water board just wants water agencies to set mandatory rules about irrigation; it’s not telling the agencies how to do that, Razak said.

“The answer really doesn’t cut it,” said Coastkeeper’s O’Malley, who points out that the city is not scoring well on the water-conservation front. This week, the city’s public relations team touted a 4.2 percent decrease in water usage in August over the same month last year, and the media trumpeted the boast. But the city also used slightly more water than last year in June and July.

Coastkeeper focuses on a section in the state’s new emergency rules that requires water agencies to trigger restrictions in the “stage” of its potential water rules that include irrigation mandates.

Under the higher level of restrictions, people could not irrigate their lawns more than three assigned days per week, regardless of whether they use a hose with a nozzle or a sprinkler system. If they use a sprinkler system, they’d only be able to water for seven to 10 minutes, three days a week, depending on the time of year.

But San Diego officials haven’t triggered the higher level of restrictions because they don’t think they have to.

So what are other water districts doing? In general, a lot more than the city on the irrigation front. Most of the 24 water agencies in the county limit irrigation days to three times per week, said Mike Lee, a spokesman for the San Diego County Water Authority, which supplies water to local water agencies like the city of San Diego.

Max Gomberg, a senior environmental scientist with the state water board, said the agency is aware of the dispute over San Diego’s water rules and will check to see whether San Diego is following the rules. If the city is not, it could face fines starting at $500 a day, he said.

Gomberg said he expects the state board to deal with the issue within the next few weeks. Meanwhile, the city doesn’t plan to do anything differently, although the mayor’s office could ask the City Council to act and change the watering rules.

Regardless of the city’s rules, irrigation outlaws shouldn’t expect to face a line of water cops armed with those doohickeys that turn off the water supply at the sidewalk. As of late last month, it didn’t appear that any local water agency had hired new enforcement crews to chase scofflaws.

San Diego hired almost a dozen water enforcers during the big drought year of 2009, but it later disbanded the team. No one in the city has been fined this year for illegal water use.