InterNACHI Septic study plan

Diagram a complete conventional gravity septic system from house stub-out to drainfield, labeling every component in flow order

Explain the function of the baffles, inlet and outlet tees, and the clear space and scum layers, and state what each protects

Distinguish between conventional gravity, pressure distribution, and mound or aerobic unit configurations by their component differences

Calculate required tank liquid capacity for a three-bedroom home using the common 1,000-gallon minimum plus per-bedroom allowance rule and note where local rules override it

Trace how a blocked outlet baffle or a saturated drainfield produces the same backup symptom at the fixture, and list two checks that separate the two causes

Identify the visual and operational differences between a distribution box, a dosing chamber, and a pump vault

List the failure indicators visible at the tank lid, the ground surface, and the house plumbing, and rank them by how urgently they point to system failure

Describe what a riser, an effluent filter, and a tank inlet inspection port each add to inspectability

Describe the soil profile evaluation steps performed during a site and soil assessment, from test pit excavation to horizon description

Interpret soil texture by ribbon and feel methods and state which textures are acceptable for an absorption area and which are not

Explain how depth to a limiting condition such as bedrock, seasonal high water table, or a fragipan constrains drainfield siting

Explain how slope, setback distances, and landscape position affect where an absorption area can legally and practically be placed

Compare trench, bed, and mound absorption area layouts by footprint, loading rate assumptions, and site constraints

Describe how a drainfield is sized from daily design flow and the soil application rate, and work two example calculations

Explain the purpose of a reserve or replacement area and how its presence is verified at inspection

Identify grading and drainage defects around an absorption area that shorten its life, and describe the correction for each

Sequence a full inspection from records review through tank lid access, tank interior observation, and drainfield area walkover

List the personal protective equipment and confined-space cautions that apply when a tank lid is opened, and state what an inspector must never do

Describe safe and defensible methods for checking tank liquid levels, measuring scum and sludge thickness, and testing baffle integrity

Draft report language that separates observed facts, probable cause, and recommended action without overstating certainty

Identify the records and documents an inspector should request before arriving on site

Explain the sludge and scum accumulation process and state the conditions that justify more frequent pumping than the usual three-to-five-year guidance

Build a homeowner maintenance calendar covering pumping, effluent filter cleaning, water use habits, and what never to flush or pour down the drain

Explain why additives, harsh cleaners, and garbage disposals affect biological treatment and system longevity

Describe how to explain inspection findings to a homeowner in plain language, including how to frame a recommendation without causing panic or false reassurance

Classify defects by severity into safety hazard, active failure, marginal condition, and maintenance item, with a defensible example of each

Diagnose the common failure modes including hydraulic overload, biomat clogging, broken laterals, crushed pipe, root intrusion, and a failed pump or float switch

Describe remediation options from repair to full replacement, and state the site and permit conditions that make each option viable

Explain how a failed system affects real estate transactions and what an inspector's role is and is not in that process

Answer 100 or more practice questions across all five domains and log every miss by domain and by root cause

Re-teach your three weakest sub-topics from your own notes without consulting reference material

Rehearse a 20-minute verbal walkthrough of an inspection, from arrival to report delivery, for a peer or a recording

Review every deliverable from weeks 1 through 7 and correct any factual errors you find