Quick answer: A real septic inspection checks five things: the tank’s structure and levels, the baffles, the drain field or spray system, the mechanical components on aerobic units, and the paperwork trail. This checklist walks through what a licensed inspector actually looks at, what each finding means, and what buyers, sellers, and owners should do with the results.
Before the visit: the paperwork
- Permit on file with the county: design capacity, layout drawing, system type. Missing permits are a finding in themselves, see the permit guide for who holds what.
- Pumping records: when, by whom. No records means the interval math starts at “overdue”.
- Maintenance contract status on aerobic systems, required in Texas, and lapses show up in county records.
- Rated vs actual bedrooms: a 3-bedroom permit under a 5-bedroom remodel is an undersizing finding that follows the property.
The tank
- Structural condition: cracks, root intrusion, corrosion (steel tanks), collapsed or crumbling lids, deteriorated seams.
- Liquid level: too high means the field is not taking water; too low means a leak out of the tank.
- Sludge and scum measurement: the honest answer to “does it need pumping”, measured, not guessed.
- Lid and riser security: unsecured lids are a safety hazard and an infiltration path for rainwater.
- Evidence of past backups: stains and residue lines inside the tank tell the history the seller may not.
The baffles
Small parts, outsized importance. The inlet baffle directs flow down into the tank; the outlet baffle keeps solids from escaping to the field. A failed outlet baffle is how a healthy field dies quietly. Inspectors check both for presence, attachment, and deterioration, concrete baffles in older Ellis County tanks erode from the top down.
The drain field or spray system
- Surface conditions: soggy stripes, surfacing effluent, odor, or the too-green grass line, the field telling on itself.
- Probe or flow testing where warranted: whether the field actually accepts water at a working rate.
- On aerobic systems: spray head coverage and condition, even distribution, no capped or missing heads, and treated water that runs clear and odorless.
- Site factors: vehicles parked over lines, structures or pools added over components, drainage directed onto the field, trees rooting into lines.
Aerobic components
- Aerator: running, drawing correct amperage, delivering air, most are 3 to 5 years from their last replacement at any given time.
- Alarm and floats: tested, not assumed. A dead alarm float is a silent failure that becomes a backup.
- Effluent pump: cycles correctly, floats free, check valve holding.
- Chlorinator: correct tablets present, feeding properly, no bridging.
- Control panel: wiring condition, breaker labeling, no bypassed circuits.
What findings mean in dollars
Most findings are small: an overdue pump-out ($300-$600), a baffle repair ($300-$900), a tired aerator ($400-$900). The findings that change negotiations are the structural ones: failing tanks ($3,500-$9,500) and failing fields ($2,000-$15,000+). The full negotiation math is in buying a house with a septic system, and current prices in the cost guide.
Who should order one, and when
- Buyers: during the option period, every time. The general home inspection does not do this job.
- Sellers: pre-listing, so findings get fixed on your schedule, not under contract deadline.
- Owners: any system you have owned five-plus years without a look inside, and any rural property purchase.
- Lenders and agents: FHA and VA transactions frequently require documentation; a written report closes the file.
Need a documented inspection with a written report in Ellis County? Real estate septic inspections, fast turnaround for option periods, or request service directly.