A group of Congress members are investigating how insurance companies use credit-based insurance scores in homeowners insurance underwriting and pricing.

The group of 20 members sent letters to USAA, State Farm, Progressive, Liberty Mutual, Farmers and Allstate requesting information about the credit-based practices.

The lawmakers said they are concerned insurance companies are unfairly raising rates based on customers' credit history.

Unlike debt, homeowners insurance products don't depend on a customer's ability to repay or their risk of defaulting on a loan, they said in the letters.

"Despite this, recent reporting indicates that Americans with weaker credit history pay significantly more for homeowners insurance," they said.

Insurers have cited increasing natural disasters, building costs and reinsurance expenses as drivers behind rising homeowners insurance premiums.

The lawmakers are asking the companies to provide information by Aug. 17.