Shrink/Swell Potential: Frequently Asked Questions

Q. I want to build a house in one of the red areas on the map. Should I reconsider? 
A. The map does identify potential problem areas but does not replace careful onsite investigation or analysis by construction engineers, land use planners and other professionals.

Q. I plan to build in one of the severe areas on the map. What can I do now? 
A. Prospective homeowners who are aware of these potential hazards can insist on special investigations and designs and expect a warranty against future problems.

Q. I own property that appears to be in a high shrink/swell potential area. Will I still be able to build a house there? 
A. Structural problems due to soil shrinking and swelling can be prevented by a foundation designed to withstand extra stress.

Q. Can someone from your agency come look at my property? 
A. The Natural Resources Conservation Service cannot perform specific on-site evaluations. It does, however, provide information like the shrink/swell map and additional soil data to all taxpayers and assists with interpreting and using the information.

Q. My engineering company would like to get the digital soils data. How do we go about it? 
A. The public may go to a map of Arizona that shows which soil surveys are in digital format. Note the identifying number (AZ???) of the survey you are interested in. Then, from the National Soil Survey Geographic Database (SSURGO) page, you can obtain additional digital soil survey information and link to the Soil Data Mart access site and download the SSURGO information. The digital soil data may also be  ordered on CD at the Geospatial Data Gateway.

Q. Is there a cost for the digital soils data? 
A. There is no cost if you choose to download the information from the Soil Data Mart web site. CD’s can be purchased for $50.00 each at the Geospatial Data Gateway. 

Q. Can anyone “read” this digital data from a home PC or is special software needed? 
A. Specific software programs are required to view and analyze the data on any PC . Many Geographic Information Systems are capable of importing and handling the SSURGO product. Contact the NRCS office or go to the Soil Data Mart web site for more information on software or system requirements.

Q. How do I get a map of my area? 
A. Your local planning and zoning office should have access to this data and may be willing to fill requests for individual maps. Many cities and counties have Geographic Information Systems for creating custom maps. If not, contact the NRCS .

Q. Is other soil related information available, i.e. flood prone soils, erodibility classes, crop yield or range production values? 
A. Yes. The SSURGO product addresses many more characteristics of soils, just as the published hard copy soil survey does. The advantage of the SSURGO product is that the data may be queried and analyzed from a spatial aspect more readily with the help of software and hardware in a Geographic Information System.

Q. How do I obtain a copy of a published soil survey? 
A. Published soil surveys may be obtained from your local NRCS Field Office. You can find the number in your phone book under U.S. Government, USDA Natural Resources Conservation Service. Offices serving the Phoenix Metro Area are the Chandler Field Office, 480-988-1078, and the Phoenix Field Office, 602-379-4934. The Tucson area is served by the Tucson Field Office, 520-887-8520.

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