Menu Close

Building Site Costs for Custom Homes in San Diego County

How Much Are Building Site Costs in San Diego County?

Many questions arise when deciding what kind of budget is needed to build a custom home. Do I even need a budget to develop this lot to build on it? What costs go into developing my lot? How much funds will be left over to build my house?  We’re going to examine a number of necessary items and the range of costs to consider when building.

Grading Site Costs

Grading is the first consideration to calculate. Typically you want to start between $10,000 to $30,000 on the lower end. Burn-down lots have situations like this. Existing pads fall into this category as well (such as in the case of demolition.) A nice flat lot, like in a subdivision also lowers grading costs. As soon as you get outside of existing flat lots, you begin to push up into a higher price point.

Grading Considerations

Considerations that influence what you want to look at include the driveway length, large rock that requires blasting, or even necessary dirt import. It’s important to meet with a  grading contractor and discuss the potential pitfalls of a lot. Site costs may initially range anywhere from 10 to $30,000, but they  can exceed much higher, even up to $200,000. Make sure that you do your due diligence and evaluate the grading with a professional during the initial stages.

BMP (Best Management Practices) Site Costs

BMPs is short for “Best Management Practices.” BMPs are stormwater management. This is erosion control during the actual construction process. Depending on the lot location, this can vary significantly. If you’re in the city of Poway, they are sticklers on BMP’s. You want to make sure you have more money in the site cost budget if your property resides in a city area that requires more. County areas, such as Julian, do not require the same enforcement. Large parcels in rural areas do not have the same kind of runoff onto streets and into storm drains. BMPs can range anywhere from $2,000 to $10,000. Be sure to adjust that based on the area of your property.

Water Well Site Costs

When city water is not an option, you must drill a water well. Water wells range between $25,000 to $60,000. This includes the well itself, the storage tank, and pumps. The site cost budget amount for drilling the well depends on the depth of that well. Contact a well driller on the front end and ask the question, “Do you know what the average depths these wells are at in this area?” Maybe this area is known for having cheap lots because every well in the area is actually dry. Check to make sure that there is good water in this area. Also find out how deep the wells have been drilled. 400 feet and 1000 feet affect the site costs much differently. So make sure you check with a good well driller that’s very experienced in the area that you’re going to be building or buying this lot.

Storage tanks are required when a hydrant is not close enough to the house or the driveway. Storage tanks typically must hold 10,000 gallons. Sometimes smaller houses only require about 5,000 gallon tanks. These tanks should be steel storage tanks. Higher steel costs have dramatically increased the costs on storage tanks. Wells also require use of a pump. You will need to install a submersible pump down at the bottom of the well, and then your pressure tanks and booster pumps will be installed in addition to the well pump. The booster pump will pressurize the house or any landscaping systems that you include on your property.

When Water Storage Tanks Are Required

There are instances where a lot has a water meter on the property but the hydrant isn’t close enough. The County Fire Department will require you to put in a storage tank that does not require booster pumps that pump to the house. They only require a gravity fed hydrant that’s close enough to the driveway. This situation does not require a well when city water is available, and enables you to opt of installing a hydrant and replacing it with a 10,000 gallon water tank. Doing so can help keep your hydrant cost down closer to the $25,000 range in the right situation.

Septic System Site Costs

Standard septic systems cost around $13,000 to $20,000 depending on the size of the system. The size is determined by the number of bedrooms in the home. A two bedroom house, for example, requires less leach field than a home with 3 or more bedrooms. When looking at land, you want to find out if the property has a completed perc test. The perc test will tell you how fast the water will seep into the ground. To determine the perc rate, an engineer or contractor will drill/bore hole into the dirt, fill it with water, and test the speed at which the water recedes. The faster the perc rate, the less leach lines required, which decreases the cost of the system. High perc rates, meaning the minutes to perc are high regarding the time it takes for the ground to absorb the water.

Some lots that do not have perc tests or rates can be calculated with the County of San Diego. You can request a comparison to adjacent lots that are touching your property, and they will accept the worst percolation rate case scenario. They’ll base your system off that size. A perc test can cost around $3,500 to $4,500, therefore some scenarios make sense to calculate the perc test for a property rather than pay for testing.

Alternative Septic System Costs

Sometimes a parcel does not have enough room to allow for a standard septic system. Sometimes high ground water, or other special circumstances, prevents the use of septic as well. These instances require use of an ATU. ATUs, which act as alternative septic systems, require quite a bit more money than standard systems. Smaller ATUs can start around $30,000 and even reach $50,000. Make sure you look into this as it may be the only option for a lot. If you do need an ATU, you must involve a septic engineer. The septic engineer will draw up all of the specs and layout necessary to submit to the county. There’s quite a bit of work that goes into that. The engineering alone will end up costing anywhere from $4,000 to $6,000.

Solar System Costs

We include solar into our site costs for every project as they are required on every new project. The typical size of a smaller custom home usually costs around $20,000. System sizes are currently averaging about 3.3 KW. You can go as large as you want to zero out your electric bill. Ground mount systems are an option, but usually cost about 30% more than a roof mount system. We have installed ground mount systems that exceeded $100,000. Many owners elect to purchase backup generators or batteries as well which can add up another $10,000 to $20,000.

Utility Site Costs

Utility costs vary a lot. The initial price for utilities can range between $15,000 to $50,000. That’s just a basic range. Some lots kick the power off at $50,000 alone, so you really need to look at this. Utilities typically include your electric, natural gas if it’s available or propane if natural gas is not available. It also includes your sewer connection and your water line. Sewer connection means that you do not need septic. Keep in mind, the utility site costs do not include the fees to actually pay for the city connection, those are sewer fees paid to the water district or whichever municipality handles that fee, which could reach $20,000. After paying sewer fees, the site costs to trench from the sewer main to the house, or even cut the street to trench, cost money to improve the project site to install the main drain line. This can get extensive, depending on the amount of road work needed to tie-in the sewer. Many times a lateral has already been stubbed out in the curb and that helps, which helps the cost. Same thing exists with the water line. You must trench from the water meter over to the house.

Trenching is an important cost that comes along with all water, wells, sewer, septic, electrical, etc. Trenching must extend to any additional tanks, pumps, remote meters, anything underground must include trenching costs. Propane trenching only requires 10 feet of separation from the house and property lines, which keeps that trenching cost low. It’s normally a couple grand or less.

Electrical Utilities

SDG&E takes a long time to get back to you these days. Start the SDG&E application at the very beginning of your planning stages. A property address is required, but getting into their system early will help the timing of your SDG&E work order.

Area Drains

Area drains are not required on every property. We do throw a rough number into the site cost budget for that line item just in case. If you have a large flat pad with potentially poor drainage, we’ll throw in somewhere between $4,000 to $10,000, just for trenching and installing area drains around the house. That’s an expense you want to consider putting in the budget, especially when it comes to your landscaping.

Driveway Site Costs

Another thing to consider is your concrete driveway. We distinguish driveways separate from concrete flatwork under porches or stoops located outside of exterior doors. Driveways fall under site costs, and flatwork falls under build costs. Driveways can be short or very long. Start your driveway budget roughly around $9 a square foot. Driveways must typically span 16 feet wide for the fire department the entire length from house to street. Make sure you calculate how much driveway you want to install based on the house location on the property in relation to the main road. Oftentimes a turnaround is also required.

Asphalt driveways, versus concrete, can range between $5-$6 a square foot which typically includes the grading, the prep work, and the laying of the asphalt. It’s a little bit less than pouring a concrete driveway. You can pour a concrete skirt just in front of your house or garage area, and then asphalt the rest of the approach to the street. You’d save a few bucks doing that. Then something to consider when you are calculating out your driveway surface, and this also applies to the house too, is the amount of impervious area on the property.

PDP (Planning Development Plan)

There is a thing called a PDP. If you exceed 5,000 square feet on the driveway by itself and/or a combination of 10,000 square feet on the lot, then the County will require you to have an engineer draw up a PDP, which is a planning development plan. They also require bio retention basins when exceeding those impervious amounts. The bio retention basins are essentially a filter for the water that runs off of these impervious areas. These basins catch the water, filter it out ,and then it drains off the property from there. The impervious area includes the roof of the house plus any concrete flatwork you had that was impervious.

Hiring an engineer and installing the bio retention bases can range anywhere between $50,000 to $100,000. That’s a significant amount of money, so make sure that you’re looking at the impervious area whenever you calculate what you want to build

Site Costs for Custom Homes

There are many different costs to prepare the property for construction. Altogether, plan on spending somewhere between $100,000 to $200,000 on site costs. Remember that your site costs can exceed well beyond the $200,000 total price. Be sure to complete your due diligence and review every detail. Keep in mind that this amount only refers to Site Costs. You might be able to find a piece of land for only $100,00, but if the site costs amount to $300,000, that lot actually costs $400,000 after making it buildable. This is a good method to evaluate the value of the land and whether or not you’re paying the right amount for it. Considering each of these site cost items will help you head off many unforeseen costs in building a custom home.

Building Site Costs for Custom Homes in San Diego County

If you’d like more information on how to buy land, buy a home, build a home or ADU, or even how to remodel your home, check out the FAQ page. If you are needing help with buying or selling your home or land visit our real estate company’s website at realpropertytv.com.



1. Request a Project Consultation Online or by Phone

2. We Will Meet With You at Your Home or Building Site

3. Establish a Budget for the Project & Start Drawing Plans

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to Top