Inside city limits, check with the City of Idalou at City Hall before starting work that changes structure, plumbing, electrical, gas, or HVAC, since permits in town are a city matter rather than a county one. Much of the land around Idalou is cropland, and a new home on acreage outside city limits generally falls under county and state rules instead of a city permit office.
Two of those rules shape a rural budget. The High Plains Water District, which covers Lubbock County, requires a permit before drilling any well expected to produce 17.5 gallons a minute or more and registers smaller exempt wells. A septic system needs a permit from the TCEQ or its local authorized agent, and the design depends on your soil. A well and septic system commonly add $20,000 to $45,000 combined to a rural build around Lubbock, and running power to a house set far back from the road adds more, so price all three before you buy land.