Kathy Onsum opened her mailbox last month and found out her home was more valuable, which will push her property tax bill still higher.

Onsum, of Fargo, bought her home in 1975 for $18,500. She paid off her mortgage last January. Assessors say her home is now worth $93,300.

Onsum, who has epilepsy and is permanently disabled, is one of almost 4,000 homeowners who qualifies for a homestead tax credit, which gives low-income elderly and disabled people a break on property taxes.

This year, lawmakers increased the credit's benefits to compensate for booming housing markets in some parts of North Dakota. Onsum said the changes make her budget workable, at least for now, but she worries about the future.

"If you kick me out of my home because you tax me too much, how am I going to afford an apartment?" she asks. "When you live on $500 a month, what kind of apartment can you afford?"

The homestead tax credit benefits homeowners or renters who are 65 years old or older, and those of any age who are permanently and totally disabled.

Legislators raised the maximum annual income one may have to qualify for the credit from $14,000 to $14,500, and agreed to a full property tax exemption for a home worth up to $67,500. The current limit for a full exemption is $44,444.

If a person owns a more expensive home, he or she pays property taxes at the normal local rate on the excess value. For example, using the newly increased threshold, the owner of a $80,000 home would pay taxes on $12,500 of the home's value.

The homestead credit's benefits, however, have not kept pace with increases in property value in North Dakota's urban areas, property assessors say.

Frank Klein, Cass County's director of equalization, said the county's residential property assessments grew between 8 percent and 10 percent for 2005.

More expensive building materials, city growth and increased housing demand, fueled by lower interest rates, are making new homes more expensive, Klein said. That increases the market value for existing homes, he said.

The trend is different in some rural areas. Alice Pekarski, a Stutsman County staff appraiser, said the number of homestead tax credits is tapering off, even though residential property values have risen about 7 percent annually since 1997.

Many people who once got the credit are no longer living, and fewer elderly qualify for the credit, Pekarski said. In Medina, the number has dropped by half, from about 50 in the 1980s to about 25 now, she said. Montpelier, which had seven beneficiaries of the homestead tax credit a decade ago, now has none, Pekarski said.

Effects in larger cities have been mixed. Ben Hushka, the Fargo assessor, said the city expected to exempt $4.5 million in property before the new law, but that rose to $6.8 million with the changes, an increase of about 51 percent.

However, Hushka hasn't seen more people qualifying for the homestead tax credit as a result of the $500 increase. Between 150 and 160 people apply each year, he said.

Burleigh County mirrors that trend, said Deb Goodsell, a secretary with the county assessor's office. Someone with the maximum credit can save $1,429 this year, versus $940 before, but the number of applicants only increased from 183 to 184, Goodsell said.

Onsum doubts the accuracy of her home appraisal. Although her home has been valued at $93,300, Onsum believes it would not bring that much in a sale.

Klein said state law requires assessors to price homes within 5 percent of their market price, which keeps values near what a homeowner could make from a sale.

"A lot of people truly believe that they can't get that, but they just haven't shopped the market," Klein said. "People don't know what it's worth until they start shopping themselves."

Bob Wood, Grand Forks County's property and records director, said assessors' estimates are accurate, but homeowners who don't agree can hire their own assessor to appeal the decision.

"It's not an exact science. It's an opinion," Wood said. "Sometimes our opinion doesn't match the owners."

Onsum said she'll pay less in property taxes this coming year because of the more generous homestead credit, despite the higher price of her home. Last year's taxes were $896.11, but that will drop to $562 this year, she said.

While lawmakers were debating changes in the credit, Onsum worried that she'd be forced to sell her home. She traveled to Bismarck to testify before a Senate committee on a homestead tax credit measure.

The taxes stretch her budget, even without a monthly mortgage payment, she said, and she believes lawmakers will have to look at the issue again soon.

"I'm not satisfied. I don't know how to go about it any more," she said. "I didn't go to Bismarck looking for a pity party. However, I need people to realize the difficulty of living on disability."