Grand Prairie is inspecting pools in the neighborhood where the city's 17th human case of West Nile virus was found.
City environmental specialists have been making rounds for more than a month in an effort to prevent the spread of the virus.
"I had 199 doors last month and already this month, I'm looking at about another 40," Andrew Krentz said.
City workers knock on doors and look for pool violations.
"We have a GIS-mapping system that can take information from building inspections," Krentz said. "They give us a list of all the permitted pools in the area. We generate a list then and create maps."
A ground-spraying truck circulated the streets on Wednesday night.
"Right after the aerial spraying, we had about two weeks with nothing going on, and now we're catching up again," said Werner Rodriguez, senior environmental specialist.
Crews are looking for stagnant pools where mosquitoes may be breeding. They toss Altosid pellets, a larvicide, into such pools to help treat them for up to 150 days.
Krentz checked a pool that was stagnant at the end of August, but it cleaned up just days later. He said seeing changes like that made him feel like he made a difference.
"It does feel like I've done my job," he said. "I think I reached out to someone in the community who needed some education, gave that education, let him know what he needed to do, and he responded back by handling that situation."
Krentz said he hoped others would follow suit and help keep their neighbors safe from West Nile virus.