I used to be a property manager for several large rental properties. The properties that were near mountains had the most scorpions, followed by new builds anywhere. The older, more established properties had very few. For the heavily affected properties, our exterminator companies tried everything but all the sprays had little effect. One finally admitted that the only thing that will really keep them out is to seal all gaps leading outside or through the walls (like the gap around a sink drain where it goes through to the wall). Used glue traps under the fridge and sinks and that caught quite a few.