Strongly recommended. A $400 inspection can prevent a $15,000 surprise. Many lenders also require it. Local contractors provide closing-ready PDF reports compatible with FHA, VA, and conventional financing requirements.
More detail
A real-estate septic inspection is more thorough than a pump-only visit. The protocol: locate and open the tank, pump it to depth, inspect inlet and outlet baffles for collapse or root intrusion, measure scum and sludge layers, inspect the distribution box for level and damage, probe the drain field at multiple points to check for saturation, run water from the house for 20-30 minutes while watching the field for back-pressure or surfacing effluent, and dye-test the field where suspected. Total time on site: 90-120 minutes. The PDF report runs 4-8 pages including system schematic, photo documentation of all inspected components, drain-field probe map, and a recommendation letter for the lender. Lenders that require septic inspection (FHA, VA, USDA, most conventional with septic-flagged underwriting) have specific format requirements; Cincinnati-area credentialed inspectors produce reports formatted to those standards. Cost runs $350-$550 in Greater Cincinnati. Cincinnati lender variance: FHA and VA septic inspection requirements are uniform nationally, but conventional underwriters vary by lender. Some require a recent pump-out, some require dye testing, some require a credentialed septic professional rather than just a home inspector. Cincinnati-area credentialed inspectors produce reports formatted to the strictest of these requirements, so the same report works regardless of which lender ends up underwriting the loan. Most Cincinnati real-estate transactions on Zone 1 properties also order a parallel real-estate radon test in the same inspection window; bundling both visits with one scheduling call is the cleanest way to keep a 14-day contingency on track.