The Federal Emergency Management Agency published a PDF that outlines the steps of the claims process: 

1. Call Your Agent

When it is safe to return to your home, report the loss immediately to your insurance agent or company and ask if you can get an advance payment to help you start recovering. Advance payments will be granted to eligible policyholders. If you send photo or video documentation, you may be able to receive up to $20,000 before the insurance adjuster inspects your damage. Normally an insurance adjuster will contact you within
a few days of starting your claim.

2. Take Photos

Before entering your home, make sure it’s safe. Take as many pictures and videos of your flood-damaged property as possible, on the outside and the inside of the building.

3. Begin Cleanup

Remove your flood-damaged items. Keep samples of items like flooring and curtains for your adjuster’s inspection. Throw away flooded-damage contents that pose a health risk, such as perishable food and pillows, after photographing them.

4. Meet Your Adjuster

Your insurance company will provide an adjuster for your claim. When the adjuster arrives, make sure he or she shows of official identification. The insurance adjuster will work with you to submit an accurate estimate of your flood loss. To ensure you receive a claim payment that reflects your flood loss and is within your policy limit, ask your insurance company about any important deadlines you need to meet.

5. Receive Final Payment

After your insurance adjuster inspects your property, you will receive a package from the National Flood Insurance Program with your insurance adjuster’s report and a check made out to you and/or your mortgage company. You should carefully review the report before depositing the check.

Find more details about flood insurance claims at fema.gov/nfip-file-your-claim.