All costs updated as of 5/7/2021
Average Site Costs in San Diego County
Grading for the house pad and driveway can cost between $10,000 to $25,000 or more depending on the size of the pad, length of the driveway and if there is any rock blasting involved.
One way to save money on the grading would be to buy a lot that had a home on it prior, that burned in the Cedar or Witch fires. If there is an existing pad from the home that was there, you may only have to over-excavate and recompact the building pad and that would only cost $5,000 to $7,000 depending on the size of the pad. You could have a significant savings there. There is also a good chance that the driveway is still in decent condition and you can use that driveway as well.
Soil Compaction Testing
Soils compaction testing is done during the time of the grading by a soils engineer. The County of San Diego requires the soils compaction reports and they are given to the building inspector at the foundation inspection which allows them to sign off on the foundation and allow you to pour the concrete slab. This will cost in the $2,000 to $6,000 range, for the soil compaction report. This can be more money if there is a large building pad.
Best Management Practices (BMP’s)
Another expense that you will have will be the BMP’s which are required for storm water management. The cost for the BMP’s will be somewhere between $1,000 to $8,000. These will include straw waddles or silt fence that get set up on the perimeter of the graded area that has disturbed soil, or it could be for sandbags that go on the road. This will control dirt erosion from the surface water running on the property.
Another site cost that you will have is the driveway costs. Most fire departments within the County of San Diego area are now requiring that you have an asphalt or concrete driveway from your property line to the home if it exceeds a 10% grade. There are also limitations on how much driveway you can have based on the impervious surface now because of a California law that was enacted. The driveway itself for the fire department must be 16 feet wide and you also must have a turnaround.
The asphalt for driveways costs $4.00 a square foot. If you’re going to pour a concrete driveway you’ll probably be in the range of $5.25 to $6 a square foot for standard gray concrete with a broom finish.
Drilling for a Water Well & 10K Gallon Water Storage Tank
Another site cost that you could have is drilling a water well. If you are not near city water and cannot hook up to a water meter you will need to drill a well.
Additionally, if there is not a city fire hydrant near your lot you will need a 10K gallon water storage tank for fire suppression.
The cost for drilling the well, installing a submersible pump, 10K gallon water tank, booster pump, pressure tanks and 4” hydrant line typically runs between $25,000 to $40,000.
If you are in an area that has very deep wells the cost can go much higher than $30,000 to $45,000 depending on how deep the well has to go. We highly recommend talking with a reputable well driller that is very familiar with that area about how deep they think they will have to drill the well to get good water. This will help you budget properly for the costs.
If you cannot connect to city sewer you will have to put a septic system in. The size and type of the septic system is based off of the amount of bedrooms in the home and the percolation rate of the soil.
If a soil percolation test has not been done on the property the County Health Department may allow you to use the highest perc rate on the surrounding lots so you don’t have to do a perc test. Doing this can save you $3,500 to $4,500 if this is the best option. The cost to install a standard septic system is typically in the $10,000 to $15,000 range, depending on the size of the home, the amount of bedrooms, and the actual perc rate.
Another scenario is the property has a high ground water problem where a standard septic system won’t work and you have to put in an alternative septic system (ATU). Those can run anywhere from $30,000 to $40,000
Utilities – Water, Electric and Propane
The remaining site costs are your utilities which are your electric, propane, and water line.
For the electric you will need to talk to SDG&E to determine what it will cost to get power to the site? This cost can vary greatly. You will need to look and see if you have a transformer on existing power poles around your property and determine if additional power poles are needed to get power to the property. If the power is underground, you will need to look for a ground mounted transformer. You will also have to determine if you need to get easements to get power to the site.
Propane lines will be installed underground. You only have to be 10 feet from the house, but you can go farther if you’d like, as long as the gas lines are sized properly. The tank location should be easily accessible for a propane truck to deliver and fill up the tank.
You will need to install a waterline to service your home. To do this you will need to trench from your water storage tank underground over to the house. You will also need to trench and install the four-inch hydrant line. It will need to be no closer than 50 feet from the house, and no farther than 150 feet away.
The distance that you must trench for the electric, propane and water determine how much it will cost. Typical utility costs are $10,000 to $20,000. You could spend less than that, but most of the time you are spending that or more.
In addition to your site costs you will also need to install a solar system. As of January 1st, 2020 California, now requires a solar system to be installed on any new custom home or ADU. A new solar system will cost from $15,000 to $35,000. The solar system can either be a ground-mounted or roof-mounted system. It just really depends what type of system works best for your lot and your home.