The National Flood Insurance Program got a makeover last year. Here’s how it works.

Virginians in flood-prone areas have more than just rising sea levels to worry about. They have rising flood insurance rates to worry about too.

Many Virginians who get flood insurance through the National Flood Insurance Program will have to pay more under the Federal Emergency Management Agency’s new model for calculating rates, which went into effect last year for new policyholders and will be used for current policyholders when they renew their policies. The changes have sparked criticisms that FEMA is not being transparent about the new calculations, with Virginia’s attorney general joining a federal lawsuit challenging them.

“It’s a complicated beast,” said Mary-Carson Stiff, director of the environmental nonprofit Wetlands Watch, which has worked with several local governments in Virginia on NFIP requirements. “It’s the government providing insurance, so what could go wrong?”

Here’s what to know.

How it works

People largely voluntarily enroll in the NFIP, although those living in homes with government-backed mortgages in high-risk flood areas known as special flood hazard areas are required to have insurance through either private companies or the NFIP.

The program was created in 1968 by the National Flood Insurance Act. It currently serves 5 million policyholders nationwide, protecting $1.3 trillion in assets.