Heavy rains this year have left standing water in the usual places: North Lawrence and near Broken Arrow Park.
And those puddles and ponds are breeding grounds for mosquitoes.
To guard against irritating bites and even worse - possible disease - people should use spray with DEET. Lawrence-Douglas County Health Department also is taking safety measures by dropping biological "mosquito dunks" into standing water to kill larvae.
"Obviously, we can't kill every mosquito in the world, so people really have to take care of themselves and protect themselves primarily," said Richard Ziesenis, director of environmental health for the Lawrence-Douglas County Health Department.
The state has no reported West Nile Virus cases in humans or horses this year, but health officials usually don't start seeing those cases until August or September, which is the peak season for the type of mosquitoes that can carry the disease.
But the amount of standing water in eastern Kansas already has made conditions ripe for mosquitoes to come out in force in the early mornings and late evenings, said Ludek Zurek, a Kansas State University associate entomology professor.
The most important preventive measures are spraying yourself and your children with repellent that includes DEET. It's also critical to treat or remove standing water around your home, including in plant pots, said Kim Ens, the health department's disease-control program coordinator.
"Do whatever you can to protect yourself," Ens said. "We all have a responsibility to help protect our neighbors, too."
Joe Blubaugh, a Kansas Department of Health and Environment spokesman, said mosquitoes that carry West Nile Virus don't need a lot of floodwater to breed, but just a small stagnant pool of water.
Lauren Jacobs, a Lawrence resident, has gotten rid of her family's kid pool, and she made sure her two daughters were equipped with repellent Wednesday morning as they played at South Park.
"(This year) is typical. It's irritating, but you just have to be very consistent about it because if they even get one chance I know they're all over us," Jacobs said.