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Louisiana Department of Health – Certified Installer of Individual Onsite Wastewater Treatment Systems Questions And Correct Answers Plus Rationales 2025. This practice covers general knowledge, state-specific requirements, system design, installation, maintenance, and regulatory compliance.
- What is the minimum setback distance from a private water well to an individual onsite wastewater treatment system in Louisiana? 100 feet This is the required separation distance to protect groundwater sources from contamination.
- What is the primary purpose of a soil percolation test? To determine the absorption capacity of the soil This helps ensure the soil can adequately treat and dispose of effluent.
- Who must approve the design of an onsite wastewater system before installation in Louisiana? The local health unit Louisiana requires approval from the parish or local health unit to ensure compliance with state code.
- When installing a septic tank, what is the minimum cover depth required over the tank? 6 inches A minimum cover helps protect the tank from damage and freezing.
- What is the daily design flow for a 3-bedroom single-family residence in Louisiana? 300 gallons per day Louisiana uses standard flow estimates for system sizing.
- Which soil type is least suitable for conventional absorption field systems? Clay Clay soils have poor permeability and can cause system failure.
- How often should a septic tank be pumped for proper maintenance? Every 3 to 5 years Regular pumping prevents solids from entering the drainfield.
- What must be done if seasonal high water table is present near the drainfield? Install an alternative system or elevate the system A high water table can cause system malfunction and groundwater contamination.
- What is the required minimum tank capacity for a 4-bedroom house? 1,000 gallons Louisiana requires a minimum capacity of 1,000 gallons for up to 4 bedrooms. 10.Which component removes most of the solids from household wastewater? Septic tank The septic tank settles and retains solids before effluent enters the soil absorption field.
18.What must be included on the as-built drawing submitted after installation? Location of all system components Accurate records are needed for future maintenance and inspections. 19.What is the primary cause of premature system failure? Lack of proper maintenance Failure to pump tanks and maintain the system can lead to expensive repairs. 20.What does effluent mean? Partially treated wastewater from the septic tank Effluent still contains contaminants that the soil must treat further. 21.Which tool is used to check trench depth? Measuring tape or rod Accurate depth is essential for system performance. 22.What is the required slope for gravity flow sewer lines? 1/8 to 1/4 inch per foot Proper slope prevents clogging and ensures flow. 23.What does a soil texture analysis determine? Proportions of sand, silt, and clay This affects permeability and system design. 24.When must an installer contact the local health unit? Before covering the system for final inspection A final inspection ensures compliance with code.
25.What is the minimum distance from a drainage ditch to a drainfield? 25 feet This prevents contamination of surface water. 26.Which type of effluent distribution is most common? Gravity flow Gravity systems are simple and low-cost. 27.What is the main advantage of pressure distribution? More uniform effluent application It helps avoid overloading parts of the drainfield. 28.Who is responsible for ensuring setbacks are met during installation? The installer Installers must comply with all placement regulations. 29.What is the first step in system installation? Stake out the system location Accurate layout prevents placement errors. 30.What is required to be posted at a construction site? Permit or authorization This shows the installation is approved. 31.How should tanks be leveled? With a transit or level Improper leveling can cause flow issues.
39.When must an installer renew their certification? Annually Renewal ensures ongoing compliance. 40.What is the required inspection frequency for aerobic systems? Every 3 to 4 months Frequent checks are needed for mechanical systems. 41.What is a sign of excessive water use? Frequent tank backups Overloading can damage the system. 42.What is the main function of a filter in a septic tank? To prevent solids from leaving the tank Filters extend drainfield life. 43.Who enforces installer compliance? Louisiana Department of Health They regulate licensing and inspections. 44.What should be done with construction debris? Properly disposed of offsite Debris can interfere with system function. 45.What is the main reason to protect the site from vehicle traffic? To prevent soil compaction Compacted soil loses absorption capacity.
46.What must be done before backfilling the system? Have the system inspected Inspections verify correct installation. 47.Which sign indicates a clogged filter? Slow drainage in the home Backups suggest maintenance is needed. 48.What does the term “hydraulic loading” refer to? Amount of wastewater applied to the soil Overloading reduces system life. 49.Who is responsible for system maintenance after installation? The homeowner Owners must operate and maintain the system. 50.When is a permit required for system repair? Always Permits ensure repairs meet code. 51.When is it acceptable to install a system during heavy rainfall? Never Wet conditions can cause soil smearing and compaction, leading to system failure. 52.What is a curtain drain used for? To divert groundwater away from the drainfield Curtain drains help maintain proper soil conditions.
60.What must be done before using fill material? Ensure it is suitable soil Unsuitable fill can cause system failure. 61.When should baffles in a septic tank be inspected? During routine maintenance Damaged baffles reduce solids separation. 62.What can cause a tank to float? High groundwater levels when empty An empty tank can become buoyant and shift. 63.How far must a septic tank be from a building foundation? Minimum 5 feet This distance prevents structural damage. 64.What does “unsuitable soil” mean? Soil that cannot treat or absorb effluent properly Systems must match site conditions. 65.Who is allowed to inspect onsite systems in Louisiana? Authorized health officials Only approved personnel can sign off on inspections. 66.What must an installer do if site conditions change after the permit is issued? Contact the local health unit for guidance Changes may require design modifications.
67.What happens if an installer fails to follow regulations? License can be suspended or revoked Compliance is mandatory for public health. 68.Why is a riser installed on a septic tank? For easier access during pumping and inspection Risers save time and prevent excavation each time. 69.What should be done if heavy equipment compresses the drainfield area? Loosen compacted soil or redesign the layout Compaction can severely limit absorption. 70.What happens if effluent enters a water well? It can cause serious health hazards Cross-contamination must be avoided. 71.What is required when installing a pump tank? A high-water alarm Alarms warn of pump failure or overflows. 72.How often should effluent filters be cleaned? Once or twice per year Cleaning prevents clogs and backups. 73.What type of pipe is required for gravity sewer lines? Schedule 40 PVC or approved equivalent This ensures durability and leak resistance.
81.What is soil loading rate? Amount of effluent the soil can accept per square foot Determines size of absorption area needed. 82.What is the function of a septic tank baffle? To keep solids in the tank Prevents solids from entering the drainfield. 83.What should be done when a system is abandoned? Pump and fill the tank with sand or remove it This eliminates safety hazards. 84.What causes effluent surfacing over trenches? Soil clogging or saturation This is a sign the system is overloaded or failing. 85.How is infiltration measured? Percolation test or soil evaluation This determines how well soil absorbs effluent. 86.What is a dosing tank? A tank that stores effluent for timed release Helps distribute flow evenly to the drainfield. 87.Who determines the percolation rate? Certified soil evaluator This ensures accurate system design.
88.What is an infiltration trench? A trench that allows effluent to seep into soil It’s the basic component of conventional systems. 89.What causes pipe blockages? Improper slope or solids buildup Good design and maintenance prevent blockages. 90.How often should mechanical components be serviced? According to manufacturer’s instructions Regular service ensures reliable performance. 91.How is the drainfield size determined? Based on daily flow and soil loading rate Sizing ensures effluent is properly treated. 92.What is the purpose of a watertight riser? To allow easy access without leaks Keeps the system sealed but accessible. 93.What is the sign of a leaking tank? Water in the excavation when the tank is empty Leakage can pollute soil and groundwater. 94.How can installers protect trench bottoms? Avoid working when soil is wet Wet soil smears easily, reducing infiltration.
- Why are serial distribution systems used? To extend the life of a drainfield One trench fills before the next is used.
- What is ponding? Standing water over trenches Ponding indicates system overload or failure.
- How is pump capacity determined? Based on flow rate and elevation lift Proper sizing ensures reliable pumping.
- What is an effluent screen? A filter that traps solids leaving the tank Protects the drainfield from clogging.
- What happens if a pump fails? Alarm will sound to alert the homeowner Early warning prevents overflows.
- Why must installer keep records? For future maintenance and inspections Good records help diagnose problems later.
- What is the sign of a leaking distribution box? Uneven flow to trenches Leaks disrupt balanced distribution.
- What should be done if tree roots invade trenches? Remove roots and protect lines Roots can clog pipes and reduce flow.
- What is the recommended minimum separation from a well to a septic tank? 50 feet Reduces contamination risk.
- What must be installed if a pump system is used? Check valve and alarm Check valve prevents backflow; alarm warns of issues.
- When should effluent samples be taken? When required by health department Some systems require periodic testing.
- What is a lift station? A pump system that raises effluent to a higher elevation Needed when site slopes don’t allow gravity flow.
- Why must trenches be backfilled carefully? To avoid damaging pipes Improper backfill can collapse lines.
- What is a sand mound? An elevated system for poor soils Used where soil depth is inadequate.
- What must be done if high bedrock is found? Install a mound or alternative system Bedrock limits natural treatment depth.
- When is an effluent filter required? Always recommended; required by code for many systems Protects drainfield from solids.
- Who must approve any design changes during installation? Health unit inspector Changes must comply with the permit.
- What does “saturated soil” mean? Soil that can’t accept more effluent Results in surfacing or backups.
- When are serial trenches appropriate? When soil conditions vary across the site They allow flexibility in distribution.
- What is the minimum depth of a septic tank outlet invert? Lower than the inlet invert Ensures gravity flow through the tank.
- Why must pipes be bedded properly? To prevent settling and breakage Good bedding extends pipe life.
- Who is responsible for making sure all setbacks are met? The certified installer Installers must follow code to protect health and environment.
- When are flow equalization devices used? To balance effluent flow over time This prevents overloading the drainfield during peak use.
- What is the purpose of a siphon in a dosing tank? To release a set volume of effluent at once This provides timed, controlled dosing for better distribution.
- What should be used to seal pipe connections? Approved watertight gaskets or sealants Proper seals prevent leaks and root intrusion.
- What happens if a distribution box is not level? Uneven flow to laterals One trench can overload and fail prematurely.
- Who is responsible for ensuring the homeowner understands their system? The installer Installers must educate the owner about operation and maintenance.
- What should be avoided near the drainfield? Planting trees or shrubs Roots can clog pipes and damage trenches.
