What should you worry about with a vacant lot purchase?

I just had a buyer purchase a lot on Big Marine Lake.  Pricey for sure with an almost 2 acre lot going for $475k.  With an investment like that you wouldn't want to find out that either the lot isn't buildable or that you need to spend an extra $40k to put steel pilings in the ground to add support to the foundation because the soils are bad.  

What you should do to protect yourself is write in a contingency to the purchase agreement to have an acceptable soil test done.  This is different from a perk test that tests the soil for a future septic system, which you should do also.  This test goes deeper into the soil than the 3 foot perk test and looks for how good the soil is to build a structure.  The concerns are clay soils or a high water table or even soils that are hazardous because in the past the site has been a dump site.   The cost is high for this test, over $1000 usually which covers the big truck coming out (see picture) and taking multiple soil readings about 10 feet deep.  But the downside of having bad soil is a much more expensive mistake.  If you find out that the soil is bad or that it will take extra costs to build on a site with less than perfect soil, if you have written in this contingency to the purchase agreement, then there is a good chance that you can negotiate the price if you still want to move forward with the purchase.  

Often in a more urban area than the rural lot on Big Marine, if there is a lot that hasn't been built on in the past, there is a reason for that.  Many developers left unbuildable lots and then 40 or 50 years go buy and someone wants to build on a lot in a desirable neighborhood only to find out after purchase that this lot was the fill site for the development or that this was the swampy spot that has since dried up a bit.  There are some signs that you can look for that will tell you if the soil is good.   Obvious signs like a low lot, or wet soils give indications that the soil is wet.   Large trees on the site can tell you that the soil is good because if it can support the trees, it can support a house.  

In addition to the soil test you should also perform a perk test.  This test runs around $600 and verifies that the site can have a septic system installed in the future.  Obviously if there is a City Sewer connection at the street this isn't necessary.  But if there isn't you need to make sure that you can install a septic system on site.  The soil tester will give you a log of soil borings and sketch a system on a map that shows where there is sufficient room for a septic system.  When you decide to build you then take this information to a septic designer who will then draw out the specs of the actual system.  

That is some big expenses for sure, but its better to protect yourself and your investment on the front end than to find out afterwards and realize a more costly mistake.