Hcad data Definition Help & faq’s(updated Sept. 2009)

Download 41.5 Kb.
Size41.5 Kb.

HCAD Data Definition Help & FAQ’s(updated Sept. 2009)

The HCAD real and personal property data is now stored and maintained in a RDBMS or Relational Database Management System. Therefore, the data structure is normalized. In other words, you may need to perform SQL joins to link to other tables to get certain data items together. Knowledge of RDBMS and SQL is critical to successfully viewing the data in HCAD’s download files.

The basic process we have developed involves importing text files (which were created from exporting our database records) into MS Access 2000 database files. The Access database (or .mdb) files contain empty tables with the structure matching the same name text files. The instructions for importing can be found in the “Import Instructions” file found at http://pdata.hcad.org/DB/Import_Instructions.pdf
There are descriptions of fields included in the Access Database file downloads. In addition, the names of the actual fields in the Access Database tables describe what the field is. For example, in the Parcel Access Database, “Owner_pct_1” is the percentage of ownership of the 1st owner, which is found in “owner_name_1.”
Record Layout information and Access field names exist on the Instructions Page under pdata.hcad.org or http://pdata.hcad.org/Instructions.html

Real Property Account Number

Q: Do account numbers change over time for a property, or do they remain static?

A: The account numbers for real property remain static.
Q: Does the account number follow the property after a sale or does the new owner receive a new account number?

A: If the sale is for the entire lot or tract the account number stays with the property.  If it involves a split out and the seller is retaining part of the property the seller retains the original account number and the buyer gets a new account for the part he or she purchased.  If the seller sells all of his property to two or more different owners the original account number is deleted and new ones created. 

Q: In some other counties, there is a property ID that is separate from the tax account number. This keeps the property itself identified separately from the owner's tax account. Does HCAD use this number?

A: No, HCAD used to store a PID number, which was very similar to this number separate number used at other counties. However, with the use of GIS, we no longer keep up with our old PID.

Personal Property Data Changes

Mobile homes are no longer located under personal property. They are under real property and the HCAD account number will always start with “600000”.

Land Use Codes

Our land use codes are now “true” land use codes. The land.txt describe records of the land for each parcel. The land use codes are used internally within HCAD for valuing the land.

Some common questions we get about land use codes:

  • "impr only" means improvement only; it is a code that says this has no land value as we only value the improvement or building of this account as in mobile homes.

  • “Override” means the appraiser manual overrides the land use value instead of being derived by the system.

  • 1000 – Res Vacant Table Val is residential used land that is vacant (could be empty lot awaiting a house to be built)

  • 1001 – Res Imprvd Table Val is residential land used to hold an improvement or building/house.

How do I distinguish the land use codes between 1001 and 2001? Basic difference is they are 2 codes saying the same thing. 1001 is table driven by the system designating residential use of land, as 2001 designates residential use of land that is hard coded, meaning the appraiser manual overrides the land use value.

Land and Land_ag

Data in the Land and Land_ag tables consists of one to many land records for each parcel or real property account record. Land data is common land used for non-agricultural purpose.

Not all accounts in Lnd_ag.txt are designated for agricultural use only. Those properties can be special value or nominal value cases, not just agriculture use. Any property can be changed to agriculture use if appropriate forms are submitted and it is accepted in our system and by our staff as agriculture use, as any property can be converted from agriculture use back to commercial or residential use by similar processes.

Land that resides on a condo is valued at 19% of the total market value. The actual size of the land that a condo sits on may be in the legal description of the header account or on the deed at the county clerk’s office.

Building Type Codes

Our Building Type codes are found in the building.txt download as “IMPRV_TYPE”, which describes the building or improvement on the land for each parcel. Building type is more of what our old land use codes were.

Building Style codes “BUILDING_STYLE_CODE” are a subordinate to the building type and are more descriptive of a building’s use.
Where are multi-family residential use codes? Multi-family use codes are in the building style codes 102, 103, 104.

Auxililiary Improvement means there is not a house on the property but there is some type of Residential Improvement such as a garage, a shed, swimming pool, etc.

Real Acct (Parcel) Information

The Real Acct or Parcel table/text file contains only one record for each HCAD 13 digit account number.


The full location addresses can be found in the site_addr_1 field, the city in site_addr_2 and zip code in site_addr_3 fields, respectively.

Neighborhood Number/Code:

Residential valuation neighborhoods are groups of comparable properties whose boundaries were developed based on location and similarity of property data characteristics. Each neighborhood in a school district has a unique identifier known as a residential valuation number. These neighborhood boundaries are maintained via an on-going office and field review. As neighborhoods change, neighborhood lines are redrawn to reflect the changes, and maintain the homogeneity of the neighborhood. Consequently, HCAD does not have a GIS subdivision polygon layer. 

Center Code

The center code indicates the individual (HCAD employee or contractor) that is responsible for working and valuing the account.


All values (except for exemption values) for an account are in the Real_Acct data files.

Building value – value of improvement – building, house

Extra Feature value – value of other feature, such as a detached frame garage or a pool


“Splt_date” is mostly equal to bogus date 12-30-1899, which equates to null or empty.

“New_Owner_Date” is most often the official date the property switched owners.

Economic Area

Economic areas are HCAD specific physical areas that we designate for the valuation of properties. We use the same economic models (income models) to value the same type of property within these economic areas. The designated economic areas are different for the property types i.e. economic area 8 for apartments is not the same as economic area 8 for retail properties.

Economic Building Class

Economic building class determines which economic model to use for this type of property. Within each economic area for each property type, we have built an income model. This aids in mass appraisal. If an apartment is in economic area 8 and it is an "A" (economic building class) property, a specific income model is used to value the property. The properties that are designated "E" economic building class are generally valued using the cost approach rather than the income approach.


DSC_cd is used to designate a Split or Combined parcel and is equal to S or C in only a small percentage of HCAD real accounts.
The shared_cad field denotes what county the parcel is now fully appraised in. For example, a shared_cad code of FB, means this parcel is within Fort Bend county and appraised there. Shared CAD law changed in 2008 and HCAD records still contain these formerly shared cad accounts.

Building Details

All buildings or improvements that are in state class codes A1, A2, A3, A4 are included in building_res.txt. All other buildings/improvements are in building_other.txt.

Size or Area

All areas are in square feet.

Heat Area—Living Area or Building sqft of a residential building.

Base Area—Building Area for commercial properties; Sum of the areas of all the base areas of a commercial property. Residential properties do not use base area.

Actual Area—For residential properties this is the base area of the house.

Gross Area—Usually equal to Actual area, except in 1+1/2 story houses. Commercial properties do not use Gross Area.

Effective Area – Please see http://www.hcad.org/Resources/EffectiveArea.asp for an explanation.

Year Built

Year the building or improvement was built is found in Building – “date_erected”.

Story Height

Story height can be found in the Fixtures data file. Once you imported data you would query the units where type = ‘STY’. If the unit’s value is 2.0, it’s a 2-story house.
Commercial buildings do not have a story height in our system as of yet.


Pools can be found in the Extra Features Access database once you import the data. You would query where cat = ‘PL’

Living Units

The “units” field you see in the “building_other” data file is the number of living units in the complex (apartment or condo.) The value may be replicated in each row, so you should only count the “unit” value in ONE of the buildings per account.

Building Count

The accurate way to calculate the building count per parcel is to count the “building_num” per each account number in the Building data files.


Exterior data contains information about sub areas of the building, such as description and sqft size, on a parcel or real property account. It is the same data one would see on an www.hcad.org details page under the “Exterior Data” section about a given account.


The percentage office on warehouses is in the Fixtures download. 

In fixture text file or access file, look for the "OWR" fixture_type and "Office Wharehouse Ratio" description.  The Units field has the percentage.


Structural Elements

The Structural element text file contains stat class codes of 'A1', 'A2','M3','O2'

Structural element2 contains 'B1', 'B2','B3','B4','Z1', 'Z2','Z3','Z4','Z5'

Structural element3 contains 'F1', 'F2','X0','X1','X2','X3','X4','X5','X6','X7','X8','X9'
Each Type Description describes the abbreviated structural element. The type description is the element and category description is the actual value of the type. For example, if the type description is “grade adjustment” and the category description is “B”, then this building has a B grade.


The HEARINGS files can be downloaded under the "Hearings" menu option. The hearing_type field designates if the hearing is “I” for Informal or “F” for Formal.

Parcel Tieback

The parcel tieback is basically a parcel relate table telling what parcels are related to the parent for sales, UDI (undivided interest), economic use (eventually) and abatements, etc.

It stores children accounts for various relationships.


The "issue date" is the date that the permit was issued.  The "year" field is used as the inspection year.  For example, an account with a permit issue date of “9/19/2006” and year “2008” was incomplete as of January 1, 2007. HCAD appraisal plans on conducting another inspection for valuation purposes as of January 1, 2008.  What this means is that for any given year once HCAD has completed their work the permit status and inspection year will be either: complete with current tax year or incomplete with the next tax year.  Any permit status with the current tax year still listed means HCAD has not yet completed work for current tax year.

Share with your friends:

The database is protected by copyright ©hestories.info 2019
send message

    Main page