Land west of Austin sells on views and acreage. It closes on water and wastewater. Most tracts around Spicewood, Dripping Springs and western Travis County sit outside any city limit, so there is no municipal tap and no sewer line. What you can build is decided by geology, county code, and a groundwater district.
Why does Travis County require five acres for a lot on a private well?
Because the county ties lot size to water supply. Travis County's groundwater availability regulation states that all lots supplied by individual water wells must be at least 5 acres. Lots on a centralized groundwater system must be at least 3 acres, or the number of lots cannot exceed the acreage divided by four. Subdivisions relying on wells also have to prove supply through aquifer testing and a Groundwater Availability Certification sealed by a professional licensed in Texas as a P.G. or P.E., under Travis County Code 482.214(b). Texas sets no statewide acreage minimum for drilling a well, so this is a county rule. Confirm the current standard with the county your tract is in.
Will the lot actually produce water?
Nobody can promise it will. Wells here reach the Trinity Aquifer, which the Texas Water Development Board describes as limestones, sands, clays, gravels and conglomerates spread across units including the Glen Rose, Hensell and Hosston, with combined freshwater saturated thickness averaging about 1,900 feet in Central Texas. Which unit a borehole reaches drives both depth and yield, so neighboring tracts can drill very differently. The Texas Groundwater Protection Committee is direct that the state cannot guarantee the work of any drilling and pump business. Use the option period: pull driller's reports for nearby wells, and flow test any existing well before the option expires.
“Land west of Austin sells on views. It closes on water and septic.”
How does septic permitting work out here?
Through the county, acting as the state's authorized agent. Travis County TNR issues residential and commercial on-site sewage facility permits for property outside city limits. Before design, TCEQ requires a preconstruction site evaluation by a licensed site evaluator or a licensed professional engineer, which includes a survey of the entire lot, a soil analysis in the proposed disposal area, and identifying other criteria necessary to determine suitability. Soil class, depth to groundwater, depth to a restrictive horizon and slope decide what system is allowed. A standard absorptive drainfield is unsuitable in fractured rock, or where drainfield slope is greater than 30 percent. Both are common over shallow Hill Country limestone, which pushes designs toward aerobic treatment, drip irrigation or evapotranspiration beds. Travis County also requires the site plan to show wells and OSSFs within 150 feet, including those on adjoining property.
Is a water district an option instead of a well?
Sometimes, and it is worth checking before you assume a well. A Texas water district is a local governmental entity that provides limited services to its customers and residents, and the types include municipal utility districts and water control and improvement districts, all supervised by TCEQ. If potable water for a subdivision will be provided by a WCID, MUD or other public water system, Travis County directs applicants to TCEQ for public water system requirements under 30 TAC 290, Subchapter D. Get the service commitment in writing. Sitting inside a district boundary is not the same as having a paid tap.
What rules still apply when there is no city permitting?
Plenty. Travis County Development Services oversees guidelines, procedures and permits for all development outside corporate city limits, and handles floodplain management, construction activity inspections and regulating subdivisions in unincorporated areas. Development is defined broadly as any man-made change to improved or unimproved real estate, including structures, driveways, right-of-way work, sewage facilities, land division and excavation, and the county's floodplain standards apply to unincorporated Travis County. A groundwater conservation district may layer on top. Southwestern Travis County GCD requires all existing wells in the district to be registered and a Well Drilling Authorization application for a new well. Hays Trinity GCD covers western Hays County, including the Dripping Springs area, and has posted that it is in Emergency Drought Stage with no new permits for production or non-exempt well construction accepted until conditions improve. Central Texas GCD handles Burnet County.
Two more items belong in the option period. Order a current survey, because access to many of these tracts runs over a recorded easement rather than public road frontage, and a driveway is itself permitted development in the county. Then check the tax status. Land appraised under 1-d-1 open-space or wildlife management use is valued on its ability to produce agricultural products, which is usually lower than market value, and changing the use triggers a rollback tax.
