Before buying land to build a new home on unsewered ground, the goal is to know, with real confidence, that a septic permit is achievable for the house you intend to build. That means a site and soil evaluation, and ideally a preliminary design, done or at least scoped before closing on the land, not treated as a step you'll handle after you already own it.
The permit sequence, at a high level, runs: site and soil evaluation, design (sized from planned bedroom count and the soil's measured application rate), permit application, and approval, before construction of the system can begin. Each step depends on the one before it, so working backward from your target house size to what the lot can actually support, before you're financially committed to the land, is the whole point of doing this early.
A seller or listing that says a lot "has perc" or "is buildable" is not the same as a filed permit or a documented site evaluation for the house you specifically intend to build; ask for the actual paperwork, or budget for getting your own evaluation as part of your due diligence on the land, not after you own it.
We hold recorded septic as-built drawings and parcel-level septic-versus-sewer classification for thousands of US counties, with the specific office that holds each county’s records. Generating a code-referenced septic design for a parcel is free.
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Get the site evaluation and, if possible, the permit process started before closing, or make the purchase contingent on a passing result. Doing it after closing removes your ability to walk away from a lot that can't support the house you want.
Not necessarily for the house you specifically intend to build; design flow depends on bedroom count, so confirm the actual permit or evaluation covers your planned house size, not just a generic pass.
It varies by jurisdiction and season (soil evaluations are often weather- and ground-condition-dependent); ask the local health department for a realistic timeline before you build your closing schedule around it.
Reviewed 2026-08-31 against the official sources linked above (where a source is cited) or, where none is cited, left deliberately general. Laws, lender overlays and local ordinances change; confirm current requirements with the county or state agency, your lender, and a licensed inspector before you rely on this for a closing.