Most drivers know that parking in front of a hydrant is illegal because it can impede firefighters from doing their job. Yet too many drivers do it anyway, including some Metrobus operators.

A fire safety advocate and a D.C. firefighter took to social media Tuesday to criticize the transit agency after a Metrobus was spotted parked in front of a hydrant in Pentagon City for about 10 minutes. They also said it’s a chronic problem.

“Is a recurring problem,” Dave Statter, a former volunteer firefighter tweeted Tuesday morning, along with a video showing the bus violation. “This isn’t isolated.”

The video, which has more than 3,000 views, shows the empty bus with its “Not in Service” message showing, parked curbside blocking a yellow hydrant — and a fire engine with its siren and lights going by. Statter, who runs the blog STATter911, returned to Pentagon City on Tuesday afternoon to find other empty buses blocking fire hydrants in the same block of South Hayes Street, in front of the Pentagon City Metro station.

Statter says it’s time for Metro to institute a strict no-hydrant-blocking policy.

“I’ve been urging @WMATA for years — after a number of incidents — to make a clear statement hydrant blocking isn’t acceptable,” Statter tweeted. “If Metro wants us to believe there’s a new safety culture, this is basic. Show some leadership.”

Metrobus responded to Statter on Tuesday afternoon via its official Twitter account, saying the information had been shared with the bus division.

“Once the division reviews the report, they will investigate and provide any necessary corrective action,” the @Metrobusinfo account tweeted. “We are glad you are on top of this!”

A Metro spokeswoman said Wednesday that bus operators are trained and expected to comply with all traffic laws.

“At bus terminals, operators are expected to use the proper layover bay and at no time should buses block fire hydrants,” spokeswoman Sherri Ly said. “If someone does see this we would ask that they report it.”

A D.C. firefighter who replied to Statter’s tweets suggested the hydrant blocking isn’t simply an occasional violation of a few Metrobus drivers.

“They don’t care about who or what they block,” Rob Chamberlain, who appears to be with D.C.'s Company 6 on New Jersey Avenue NW., said in a tweet Tuesday, which he later deleted. “They block the front of the firehouse EVERY SINGLE DAY and we are delayed getting out. Metro bus drivers have no regard for emergency vehicles or anyone else for that matter. #WMATASucks

The Washington Post, which captured a screenshot of the tweet before it was deleted, was unable to reach Chamberlain.

D.C. Fire spokesman Doug Buchanan said he was not aware of repeated incidents that could jeopardize response times, nor of specific discussions DC Fire and EMS has had with Metro regarding buses blocking or obstructing fire hydrants in the District.

“I can assure you that we would not hesitate to reach out to any public or private entity whose vehicles block fire hydrants,” Buchanan said. “Fire hydrants are crucial to our operations on fire grounds and any delay in accessing fire hydrants only makes the heroic work conducted by D.C.’s bravest every day more difficult under already dangerous circumstances.”

In D.C., the law is clear: No parking allowed “within 10 feet of a fire hydrant.” Violators face a $50 fine. The District also recently set the fine for failing to yield to an emergency vehicle at $100.

In Arlington, where the empty Metrobus was spotted blocking a hydrant Tuesday, it is illegal to stop, stand, or park within 15 feet of a fire hydrant or entrance to a fire station. Drivers face a fine of up to $55.

Statter, a former TV reporter who covered the interactions between Metro and fire departments, says the repeated incidents he has documented of buses blocking fire hydrants — even when there is a Metro police patrol parked in the next block — show the lack of enforcement of the law.

“This is a cultural thing,” he said in an interview. “At Metro, blocking hydrants is not a priority.”

He said he understands Metro workers need to take breaks but said it shouldn’t be at the expense of safety. In his tweets, Tuesday, he suggested a policy.

“Since @wmata can’t muster the courage to say this, let me write the tweet for them: ‘No one, including Metro’s employees, should block fire hydrants with a bus or any other vehicle,’ Statter wrote.