There are lots of things to think about when clearing land to build a house. From drainage to soil to septic system placement, the number of considerations can be overwhelming. From the hundreds of houses I've built, these are the top three mostly costly things we encounter when getting land ready for a new house.
Keep in mind that we build houses in central Oklahoma. If you live elsewhere, your main issues might vary, but you can still use this list as a starting point for key things to consider when buying land or deciding where on your land to build.
1. Steep slopes and creating proper drainage
One of the most expensive things to do when preparing land for building is moving dirt, trees, and/or debris. Obviously you need a flat place on which to put the house. The steeper the natural slope of the land, the more dirt you'll need to move. If you have to move dirt from off-site, hauling that dirt can be really expensive. The same goes for hauling dirt away.
Another thing to keep in mind is you not only need space to fit the house, but also a clear distance around the perimeter to create sloping land away from the house for proper drainage. When the land is particularly steep, you might even need to build retaining walls to hold back the land.
Take drainage into account when measuring out how much land you'll need to clear and shape. Assuming the land is big enough (more than a city lot), plan to clear and move dirt for an area that's at least 10 feet bigger in every direction than the house's footprint.
2. Organic soil or hidden debris or structures
This is a weird one, and it can be tough to see initially. I've grouped two things together because the solution for both is similar. In the case of organic soil, most of the time the issue is that there are lots of decayed leaves and other stuff that Mother Nature has deposited over the years.
The top several inches (or feet) of dirt consists of decaying organic matter that won't support your house very well. Removing it requires a backhoe or front-end loader and a dump truck and potentially many hours of work. Once the organic layer is removed, you'll have to fill the void with good soil and compact it. It is shocking how many loads of dirt it takes to fill a hole.
You run into the same issue when you start to clear your land and discover an old septic tank, buried burn pit, or some other structure that has to be removed and backfilled.
3. Access for and placement of utilities
When building on rural land or acreage, utilities such as electricity, natural gas, water, and sewer are not typically readily available or accessible. Getting access to these utility services can be costly for a couple of reasons.
Clearing the path for utility lines
First, you might have to clear a path for overhead or underground power lines, or underground gas, water, or sewer lines. Second, the utility company or city might charge you by the foot to run service to your location.
Water and sewer
If there is not yet access to water and sewer in your location, you'll need to plan for a well and septic. Keep in mind your state's environmental department has requirements for how close a well can be to a septic system, so you'll need to plan accordingly. I've seen people make the mistake of placing the home in such a way that they didn't have the necessary distance for both the well and septic. In order to install a well, they had to negotiate purchasing additional land and getting an easement to put the water well on someone else's property.
Also, with a septic system, you have to take gravity into account. Make sure that the sewer outlet from the house can flow downhill to the septic tank, but not so much that the tank will need to be buried too deep. There's a limit to how deep the tank can be—you can read more about septic system installations here. Aerobic systems are more tolerant of a deeper tank, but conventional systems rely on gravity flow to work, and if the tank is too deep, the lateral lines will be too deep and the system won't work.
The above three items are only a few of the considerations when it comes to how much it costs to clear and prepare land for building a house. The key thing to keeping costs under control (or at least predictable) is planning: take the time to do research on the land, talk to local contractors about issues they've seen when working in the area, and hire a builder with lots of experience building on challenging sites.