Wichita ? Floodwaters ebbed Thursday in southeast Kansas despite overnight rain that swamped other parts of the state.

The contaminated floodwater has strained supplies of clean drinking water for cities and rural water districts in southeast Kansas, prompting officials to truck in several semitrailer loads of bottled water for affected residents.

“Getting bottled water to communities is a priority,” said Sharon Watson, spokeswoman for Kansas Emergency Management, noting several water treatment facilities were flooded and without power.

Water boil advisories were issued for several cities and rural water districts in southeast Kansas and northeast Oklahoma because of fears contaminants may enter water supplies.

The U.S. Army Corps of Engineers is helping assess damage to water treatment plants in Fredonia, Coffeyville, Independence, Neodesha, Labette, Osawatomie and Chautauqua.

The Federal Emergency Management Agency is sending trailers loaded with bottled water into Fredonia, Longton and Coffeyville. Each trailer provides enough water for 5,000 people per day, and the agency plans to send in 10 trailers a day until further notice, according to the adjutant general’s office.

Meanwhile, the half inch of additional rain that fell across the waterlogged area overnight was not expected to affect river levels, which had peaked earlier at record levels in southeastern Kansas, the National Weather Service said.

“The rains that caused these things were nearly 20 inches total over several days. These are large drainage areas that feed these rivers, so a half inch over those areas wouldn’t create any additional flooding at all,” said Jim Putnam, a hydrologist with the U.S. Geological Survey.

The Verdigris River at Independence, Fall River at Fredonia and Marais des Cygnes River near the Missouri state line all reached their highest recorded levels in recent days. Meanwhile, the Neosho River near Parsons hit its highest river stage since 1951.

Those river levels are expected to continue slowly falling over the next several days.