Building on your own land is different from building in a subdivision. No developer already ran the water, sewer, and electricity to the curb. You're responsible for all of it — and the county isn't going to remind you.
After 20+ years building in Guadalupe County, here's what we see people miss most often.
Water: Well vs. City
If your land is outside Seguin city limits, you're almost certainly on well water. Wells in this area typically hit good water at 200–400 feet. Cost: $8,000–$15,000 depending on depth.
What most people don't account for: water quality testing. Guadalupe County water often has high mineral content. A water softener and filtration system runs $2,000–$4,000. It's not optional if you want your fixtures to last.
Sewer: Septic Systems
No city sewer means a septic system. Guadalupe County requires a percolation test ("perc test") before issuing a septic permit. This determines whether your soil can absorb effluent and what size system you need.
Important: The perc test determines your leach field size, which determines where you can place your house on the lot. Do this before you finalize your home's placement — not after.
Cost for a standard aerobic system: $6,000–$12,000. If the soil is clay-heavy (common near McQueeney), you may need an aerobic system with sprinklers — closer to $12,000–$18,000.
Electricity: Getting Power to the Site
Call Guadalupe Valley Electric Cooperative (GVEC) early. If your property isn't near an existing line, running power can cost $5–$15 per foot. A quarter-mile run? $5,000–$15,000.
GVEC also requires a site plan before they'll even bid the job. We handle this for our build-on-your-lot clients, but if you're pre-shopping land, call GVEC before you close on the property.
Permits: Guadalupe County vs. City of Seguin
Inside Seguin city limits: City of Seguin permits. Outside: Guadalupe County. The county process is generally faster (2–4 weeks vs. 4–6 weeks for the city). Both require a site plan, septic approval, and a foundation plan engineered for local soil conditions.
Soil: The Unsexy Variable That Can Kill Your Budget
Guadalupe County has expansive clay soils in many areas. Shrink-swell means your foundation needs to be engineered for it — typically a post-tension slab or pier-and-beam. A standard slab on expansive clay is a warranty claim waiting to happen.
We always require a geotechnical report before we finalize foundation design. Cost: $1,500–$3,000. That report dictates your foundation type and cost. Skip it, and you're guessing with the most expensive part of your house.
The Bottom Line
Building on your land costs $20,000–$45,000 more than building in a subdivision — mostly for utilities and site prep. It's not a surprise if you plan for it. It's a disaster if you don't.
