Harris County Appraisal District (HCAD) values are much less reliable for older homes than for homes built after 1990. For homes built in 1990 or later, HCAD is typically within 8% of market value. However, the error rate is 20% for homes built before 1960, 18% for homes built before 1970, and 15% for homes built before 1990. Including all homes, HCAD’s valuation error rate is typically 14%. HCAD’s value is off by 20% or more for about 15% of all homes in Harris County.

Homes in Harris County

Year Built Typical HCAD Error Rate
Before 1960 20%
Before 1970 18
Before 1990 15
1990 or later 8%

Harris County Appraisal District uses a process termed mass appraisal to value the 1.7 million tax parcels in Harris County. A licensed appraiser doing an appraisal for a home is usually accurate within 5 to 10%. Appraisal is not an exact science; it involves much judgment. Further, there is limited information available regarding the subject property and comparable sales even when doing an individual appraisal.

Mass appraisals are less reliable since the valuation does not include the appraiser inspecting the subject property or the comparable sales. HCAD’s information on the comparable sales is frequently inaccurate, based in part on the resources they have to analyze the sales.

Incorrect information regarding the subject property is one of the key factors causing errors in HCAD’s valuations. HCAD did not exist before 1980, so with rare exception, an HCAD appraiser has never seen the inside of homes built before 1980. HCAD has to guesstimate the grade of condition, level of remodeling and overall condition of homes built before 1980. HCAD appraisers measure and estimate the grade of condition of homes built after 1980. However, they generally have little or no information about the remodeling or condition.

Monday, June 2nd is the deadline to file a property tax protest. Texas law requires that home owners must file a property tax protest to obtain a copy of the appraisal district’s evidence. In most cases, the appraisal district’s evidence supports a reduction in value. Most property tax protests are successful. This is not surprising since the typical error rate for homes on Harris County is 12%.

HCAD’s data errors are the underlying cause of HCAD over-taxing African American areas. In many cases they over-state the condition of the house. They then use the sales price for homes in good condition to value homes in fair or poor condition. Homes in African American areas are seven times as likely to be over-valued by 10% or more as homes in primarily Anglo areas.

For more information, contact Patrick O’Connor at 713 822 8613 or poconnor@poconnor.com.