Check to see if your county or city has a GIS site- Geographic Information System, IIRC. You can look up the lot and check topography and flood zones. The flood zone map should tell you if it's something you want to consider. The county or city may have flood zone maps on file, if they don't have GIS. I wouldn't consider anything in a '100 year' flood zone, and with the wacky weather these days, I'm not sure I'd even build in a 500 year flood zone. It seems like we have the 'storm of the century' every year these days! As for the water running down the hill, make sure that your basement has all of the latest waterproofing and drainage technology, and that the yard is graded away from the house, so water can't pool there.

Don't trust what people casually tell you, even the realtor. They may not know, or (gasp) might tell you an 'alternate fact'.

Good advice from mushcreek! 12% is pretty steep, and will require some special expertise in the concept for the house, and the supporting foundations, in addition to strategies to deal with surface run off.

For example, a house from a plan factory or builder, normally designed to be built on flat terrain, will not be a good fit for land with such slope.

Does your area have expansive soils--soils with a high degree of clay? If so, slumping and slides may also be a possibility. A geotechnical engineer can tell you what you will have to do in such cases.

Good luck!

Another small, but important(later) is how the lawn would be maintained. 4 cycle lawnmowers would be starved of oil and seize on a grade like that. That means 2 cycle in necessary(or now electric), and 2 cycle engines are discouraged(air pollution).

Also, the grade for the drive and/or entry may be too steep.

We had a house built on a lot that had an elevation change of about 60 feet in the 340' length. The house was built in the center of the grade. The ground was terraformed to direct rain runoff/snow melt around each side. We have very clayey soil locally, and ran into a couple of problems later on. As ground/house settled, a crack appeared(easily fixed) and some of the swaling changed.

We lived in a house on a creek side for 20 years in San Antonio. The good news is all the soft soil had been washed away years ago from water and slope. When we added a room we had bedrock that had to be jackhammered to get down 2 inches to make a base for new concrete piers. There was absolutely no foundation shifting since 1939 when the house was built. I don't know what the slope was but we could stand up underneath the house at the low side.

We found our county's GIS to be vary valuable in searching for a suitable lot. In additional to slope, look at other geological hazards such as slope stability, liquefaction, and NEHRP (National Earthquake Hazard Reduction Program ) classification if applicable.

We were looking at a lot with a slope greater than 15 degrees and had a stability classified as severe erosion hazard area (not unusual for the area). We passed on the lot even though it had a nice view. Six months after we moved on, the lot washed away and took a large newer home on the downside of the slope with it.

Actually, the grade is abit more than I thought. Its about 24% from side to side in the build-able area of the lot, and 3% from back to front. So I could see this being like a stacked/layered house, following the slope of the hillside. But this is not on a big hill or mountain, the top of the hill is just 28 ft' higher than the building site, about 360' away. The very bottom of the hill is 42' lower, and about 1300' away.

Do your due diligence before taking any actions! :-)

"alternate fact". That should go on the list of quotables for this year. Just saying...

Here's a topo view of the site. For reference, the width of the box is about 90 ft.

Looks like a left-over site for some good reasons! What do you know about soils conditions?

It looks like the site slopes from the east side of the site down to the west side of the site (assuming north is up). There are a lot of factors involved, but this could be opportunity for a very creative design.

Yep, north is pointing up. This lot is in an older well established community, where the homes were built like 40 years ago. It's not in my illustration, but there is a house on the lot to the right, where it is flat. These three lots used to be one big lot that belonged to that house, and the owners split it up into 3 lots to sell two of them and make some extra money. Maybe they got tired of mowing and maintaining it as well. I suspect when the original developer parcelled up the land, they made this area one big lot, because otherwise they wouldn't have been able to sell all the land.

Virgil - I know nothing about the soil conditions, I am abit worried that it might shift over time. There are mature trees on the lot and they do appear to be growing straight though. How can I find if the land will hold a house?

Mark - I would like a creative house. Part of the reason I'm considering custom vs tract is because I like something unique and not cookie cutter. Just hoping that does not mean double the price.

What kind of engineering expenses should I expect to put a 2500 to 3000 sq ft house on a lot like this? I do know that public water and sewer is available at the street, but it has not been run to the lot where the house would be located.

Thanks,

Mike

@HandyMac - What problems did you encounter later on?

So should I decide to make an offer on this lot, what contingencies should I put in place?

It may be a good idea at this point for you to find a local architect (and builder) that would be willing and able to design an appropriate home for this site and your needs. They will be able to assist you through the whole process.

If I had made an offer on the 30º slope lot--I'm still so tempted--it would have been conditional on "satisfactory" soils and engineering reports. IOW, leaving me a complete out.

And it hardly sounds like there's any rush on the lot you're interested in. Then, as advised above, seek out experienced local pros for input as to costs and feasibility.

You can make a feasibility contingency offer. We did for a three week period and it allowed us enough time to get a geotech report for the lot and to make a couple of modifications to our plan to ensure it was a suitable parcel.

Mike wrote, "...Virgil - I know nothing about the soil conditions, I am abit worried that it might shift over time. There are mature trees on the lot and they do appear to be growing straight though. How can I find if the land will hold a house?..."

Mike, you need a geotechnical engineer (sometimes called a soils engineer) to perform soils tests and give recommendations for proper foundation design based on the actual soils conditions. Otherwise, you risk making another photo for Worthy! :-)

12% is a hell of a hill. I've got enough of a slope to put a story and a half roughly between one side and the other. It did give the architect some opportunity to do some stuff you can't do with a flat lot.

Like what Ron?

Design constraints aren't necessarily bad because they provide something to work off of. Here's one "on the boards" that's on a 28% slope (13' drop over a 46' run). Had could only be 28' wide to boot and the house works fine. It's a front to back slope as opposed to your side to side but slope direction will have no effect on a creative solution.

Here's a home built on a challenging sloped city lot .