EVERETT — A former Snohomish County stormwater technician failed to show up for a third of the hours he logged on his time cards during a two-year period, a state audit concluded.

In light of the review, county leaders have promised to strengthen policies for tracking some employees who work outside the office. The county also plans a civil lawsuit to recoup more than $50,000 in wages and benefits.

That’s what auditors estimate the former surface water management engineer owes county taxpayers for more than 1,300 hours of work he claimed without actually showing up.

Prosecutors said no criminal charges will be filed because they would have difficulty proving a crime with the available evidence.

State auditors released their findings Tuesday.

The employee worked in the surface water management division of the public works department. At the time, that department was overseen by Aaron Reardon, the former Snohomish County executive.

The county started investigating on its own, once problems were discovered, records show.

“We take those kind of things seriously in surface water,” county Public Works director Steve Thomsen said Tuesday. “We are taking steps to make sure it doesn’t happen in the future.”

The employee resigned in January 2012, after about four years on the job, Thomsen said.

The former employee’s regular shift involved working 6 a.m. to 4:30 p.m. with a half-hour lunch break, state auditors reported. County budget documents show the man earned about $60,000 per year.

The job entailed inspecting structures such as storm drains and catch basins. It also involved following up on complaints about situations such as flooded driveways.

The worker’s absenteeism came to light after a co-worker reported suspicions about him arriving late for work. County finance staff later asked the State Auditor’s Office to review their findings.

State officials agreed with what the county turned up.

“The county gets plenty of credit for bringing this concern to our attention for confirmation,” said Thomas Shapley, spokesman for state auditor Troy Kelley.

The results included building-entry records suggesting the technician missed 1,331 of 4,297 hours reported on his time sheet between Jan. 1, 2010, and Jan. 31, 2012. That added up to $50,555 — nearly $40,000 in overpaid wages and more than $10,000 in overpaid benefits.

Auditors also noted $1,170 in related investigation costs.

They recommended the county pursue civil action to recoup the money.

“We’re going to follow through,” Thomsen said.

During the investigation, the county also sought help from Everett police.

“Ultimately the case was closed due to insufficient evidence,” Everett Police Officer Aaron Snell said.

Snohomish County chief criminal deputy prosecutor Joan Cavagnaro said it would have been difficult to prove elements of a crime, such as deliberate deception by the former county worker.

County Public Works managers are improving how they keep track of employees in the field, Thomsen said. They’re moving away from paper records, toward an automated time-keeping and scheduling system.

The county also plans to install global positioning system devices on all surface water vehicles to keep track of their whereabouts.

Noah Haglund: 425-339-3465; nhaglund@heraldnet.com.