Cullen Morris had been lifeguarding for about two weeks when he saved a girl from drowning at the Northwest Branch Pool in Silver Spring. “For the first couple of days [after the save], it looks like everyone is drowning,” he said. (Dan Gross/THE GAZETTE)

Cullen Morris, a 16-year-old lifeguard at Northwest Branch Pool, in Silver Spring, was on duty when a 13-year-old went down the pool slide and didn’t come up. He initially thought she was holding her breath, but after a couple of seconds, he dove in.

“At first, it didn’t look like she was struggling,” Morris said. “After a couple seconds, I started to get a little bit nervous.”

When he reached the girl at the bottom of the pool, she was almost unconscious and choking on water, Morris said. He brought her to the surface, and other lifeguards helped him get her out. Emergency medical technicians arrived and took her to a hospital, he said.

Morris said he had been lifeguarding for only about two weeks before he completed the “save,” as a rescue is known. He got back into the lifeguard chair after he knew the girl was safe, but his nerves were shaken.

“For the first couple of days [after the save], it looks like everyone is drowning,” Morris said. The girl was a guest of a pool member.

Colleen Hamm, 23, was ready for her rescue of a child at the Little Falls Swimming Club, in Bethesda, managed by Bethesda Aquatics.

Hamm has been a lifeguard at the pool since she was 15 and had never needed to make a save before this summer.

It was the middle of the week, and the pool was crowded with a swimming and diving team practice, as well as recreational swimmers. Hamm and two other lifeguards were keeping watch.

A group of 12-year-old boys was playing in the diving well when one went underwater. The guards later found out he had gotten caught underwater and was trying to pull on his friends’ legs so they could help him back to the surface. But his friends thought he was playing and swam away.

The lifeguard in the chair, Abby Fry, noticed the boy sinking and blew the pool’s emergency whistle, three short blows. Hamm told everyone to get out of the pool. Fry dove in and brought the boy to the surface. He was unconscious, and Hamm started CPR.

“I was only doing CPR for two minutes, but it felt like forever,” she said.

On the second round of CPR, the boy opened his eyes and responded to Hamm and Fry. He had no idea where he was or what had happened to him.

After he was on his way to the hospital, people congratulated the lifeguards on the rescue.

“They were telling us they were happy to know their kids could come here and be safe without their supervision,” Hamm said.

If Fry had not noticed the boy was in trouble, the save might not have happened, Hamm said.

“The margin of error is very small, so lifeguards must be very careful and vigilant,” said Chuck Montrie, president of Bethesda Aquatics.

RSV Pools President Scott Vincent said a lifeguard’s “ultimate goal is prevention.” RSV manages King Farm Pool, in Rockville, along with 54 others throughout Montgomery and Frederick counties.

Rachel Citren, 15, demonstrated the results of the training after saving a 5-year-old boy at King Farm.

While on duty, she noticed the boy was a weak swimmer. When he began drifting toward the deep end, she focused on him.

He couldn’t reach the wall and started struggling to keep his head above water. Citren dove in and guided him to a ladder, where his mother met her to pull him out.

This was Citren’s first save after starting her job Memorial Day weekend.

“As a lifeguard, I have to go in to work with the mind-set that today someone will need my assistance and that I will make a save,” she said in an e-mail.

Vincent estimated that his lifeguards make anywhere from 25 to 100 saves a summer and have made about 10 so far this year.

All lifeguards must be certified in basic first aid and CPR as well as be able to use an automated external defibrillator, which sends an electric shock to a cardiac arrest victim’s heart to steady the rhythm. They must also be able to tread water without using their hands, swim with multiple strokes and perform a variety of saves. There is also a written test that must be taken every two years for lifeguards to keep their certification, Vincent said.