Floodwaters be contaminated with debris as well as high levels of bacteria, chemicals, waste and other pollutants, which can cause prolonged health risks, experts say.

Several flood warnings and watches were issued across Central Texas on Sunday, including in the areas inundated by deadly flooding last week.

At least 27 campers and counselors were killed at Camp Mystic during the devastating Texas floods. Some are still missing.

The risk of the catastrophic flooding that struck Texas Hill Country as people slept on July 4 and left at least 120 dead was potentially underestimated by federal authorities, according to an ABC News analysis of Federal Emergency Management Agency data, satellite imagery and risk modeling.

Slow-moving storms will bring a risk of flash flooding to Texas both Saturday and Sunday. Here's where the greatest risk will be.

In areas that see rainfall and increased cloud cover, temperatures are expected to remain below seasonal averages into next week, providing some relief from the summer heat. However, much of central and southern Texas, areas in the recovery phase from the catastrophic flooding, will face dangerous heat instead of renewed flooding.

Some regions in the mid-Atlantic are also facing risks of flooding. On Sunday, Tropical Storm Chantal flooded parts of North Carolina, where more than 10 inches of rain fell near the Chapel Hill area. The Haw River, near Bynum, North Carolina, crested to nearly 22 feet, the highest crest on record there, as a result of those heavy rains.

Kerr County failed to secure a warning system, even as local officials remained aware of the risks and as billions of dollars were available for similar projects.

There are questions over why oversight was eased at Mystic Camp as it expanded in a hazardous floodplain, the AP reported.

President Trump is visiting Texas to meet with first responders, local officials and families of some of the victims in the aftermath of the catastrophic flooding. NBC News Priscilla Thompson reports from Kerrville,