Question of the Day - 03 July 2022

The number-one reason is caliche (pronounced "kuhLEEchee").

Caliche is a rock-like material that occurs in deserts and semi-arid areas when groundwater that’s rich in calcium carbonate (lime) rises up through the soil via capillary action and evaporates, depositing an impermeable layer beneath the surface that’s as tough as concrete.

These deposits are erratic in terms of thickness, hardness, and extent, which makes interference with below-grade construction difficult to predict. Even known deposits create major headaches, due to problems in their removal -- everything from a pick and shovel for thin layers and a jackhammer for medium-thick layers to D6-7 Caterpillars for deep layers and explosives for planting large palm trees. 

It’s possible to have a soil test performed prior to digging foundations for houses, which is advisable if you're considering building a basement, because if caliche is discovered, you could be looking at a sizable bill if you want to dig down through it. Indeed, the very word "caliche" has been known to strike terror into the hearts of home builders and jack up a contractor's bill by tens of thousands.

Otherwise, according to the City of Las Vegas Building & Safety Department, there are no impediments in the form of planning codes or building regulations that prohibit basements, but they did offer a couple other explanations as to why they're unusual in Las Vegas.

The issue of flash flooding is one. Although this is a very dry city for much of the year, dramatic thunderstorms do occur, particularly between July and September during the monsoon season. Due to the steep mountainous terrain surrounding the valley and the fact that the ground is so dry for much of the year, there’s a problem with surface runoff leading to flash floods. If your home is on the floodplain, as many are, a basement can turn into a huge liability when floodwaters show up.  

The second and perhaps most widely applicable answer to your question, is not so much a practical consideration as simply an issue of custom. Although our Building Department source confirmed that he personally knows of several houses in the area that do have basements, it’s just not the established style in Las Vegas, where homes have traditionally been based more on the single- or two-story "ranch" model.

We suspect, coming full circle, that that's because of the caliche.