He was listed in critical condition late Friday, officials said.
The boy's mother called 911 about 2 p.m., Snohomish County sheriff's spokeswoman Shari Ireton said. The boy apparently had disappeared under the water.
A bystander pulled the boy to the river bank, and family began resuscitation efforts, Ireton said.
The incident was reported near the 12700 block of Dubuque Road, between Lake Stevens and Snohomish.
The boy was taken to Seattle Children's Hospital for medical treatment.
The boy, who weighs about 80 pounds, reportedly got caught on a small log in the river and the pressure of the water took him under, Snohomish County Fire District 4 battalion chief Craig Heike said.
"Moving water creates a lot of pressure," Heike said. "Don't underestimate the amount of pressure the water can push against the body."
Local safety experts say people need to exercise care around moving water. Rivers in Snohomish County run cold and fast this time of year, and hide hazards, including logjams and other debris. They recommend not swimming alone, not using pool toys in the river, and establishing rules for the family around the water. It's also important to wear life vests and to be aware of the depth of the water before jumping in or diving.
Heike said it was fortunate on Friday that there was adult supervision nearby.
As the summer heats up, local fire districts are gearing up for water rescues.
Temperatures over the weekend in Everett could reach 75 degrees, according to the National Weather Service in Seattle.
Eric Stevick: 425-339-3446, firstname.lastname@example.org
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