A home is surrounded by floodwaters from Tropical Storm Harvey on Monday, Aug. 28, 2017, in Spring, Texas. (AP Photo/David J. Phillip)

The estimated bills for Harvey are just now trickling in and they are preliminary, but a couple of facts are becoming clear.

First, Harvey will be rank among the costliest hurricanes to strike the U.S.

Second, a very large portion of the bill will wind up on property owners.

Among the more credible estimates for Harvey's damage was issued on Wednesday by RMS, the risk modelling firm that works for insurance companies. Their model incorporates everything from property values and land elevations to river gauges and rainfall totals. While previous estimates had run from $30 billion to $160 billion, they put the economic costs of Harvey at between $70 billion and $90 billion.

That burden, moreover, is expected to be borne by property owners.

"The majority of these losses will be uninsured," Michael Young, a senior director at RMS said in a blog post.

The primary reason that the nation's insurance companies are off the hook for the damage is that most of the destruction came from flooding, which is not normally covered by a standard home insurance policy. They cover wind damage, not floods.

As a result, the portion of losses in Harvey that are covered by the insurance industry may be relatively tiny.

AIR Worldwide, another catastrophe modeling firm, estimated industry insured losses at between $1.2 billion and $2.3 billion. An analysis by another firm, CoreLogic showed that insured losses for residential and commercial properties would run between $1 billion and $2 billion from wind and storm surge damage - not flooding. Another firm, S&P Global placed the figure at $6 billion.

If they're right, in other words, standard insurance coverage may cover less than ten percent of the Harvey bill.

The other way that property owners may have coverage, of course, is through flood insurance, which is typically provided by the federal government.

But the vast majority of people in the  areas stricken by the floods did not carry flood coverage. In fact, only 17 percent of homeowners in the eight counties most directly affected by Harvey have flood insurance policies, according to a Washington Post analysis of Federal Emergency Management Agency data.

Overall, what that means is that the responsibility for the huge bills will mainly lie with the property owners in Harvey's path.