Last updated and sources checked: September 19, 2026.
Treatment improves wastewater quality. Dispersal delivers the liquid to an approved receiving area, where soil can provide additional treatment. A complete onsite system must do both. Calling a system “aerobic,” “drip” or “pressure” tells you something useful, but none of those words alone describes the entire arrangement.
Use this guide to read equipment lists alongside the complete Kansas City septic planning guide. The discussion is conceptual; it does not specify sizes, depths, pipe layouts or operating settings.
Follow the wastewater, one function at a time
| Function | Component you may see | Question for the proposal review |
|---|---|---|
| Collect and separate | Septic or pretreatment tank | Which wastewater enters, and what is retained for later removal? |
| Provide additional treatment | Aerobic unit or media filter | What performance is this stage intended to achieve? |
| Store and deliver a dose | Pump tank, pump, controls | How does delivery match the approved receiving field? |
| Distribute across the field | Gravity network, pressure piping or drip tubing | What dispersal arrangement is included in the design? |
| Receive and further treat | Evaluated soil, or an approved mound and underlying soil | What documented limitations govern this area? |
| Observe and maintain | Access points, alarms and monitoring provisions | How will a service provider verify operation? |
The table is a reading aid. Some functions share one physical tank; others use several components. Ask for a labeled flow diagram of the actual proposed system so that the arrangement can be understood without guessing from the number of lids in the yard.
What does the septic tank do?
The tank separates materials and begins treatment. Heavier solids accumulate below the liquid, while lighter material collects near the surface. Remaining solids need removal. The liquid leaving the tank is still wastewater, and its destination is a necessary part of the design. MU Extension, conventional septic operation.
An effluent screen is a separate protective component at or near the tank outlet. Its role is to limit solids traveling downstream, and it needs accessible servicing. It is not a replacement for the treatment or dispersal stages. EPA effluent-screen fact sheet, description and maintenance.
On a proposal, “tank replacement” should therefore trigger another question: what evidence supports keeping the rest of the system? A new tank does not itself document the condition or suitability of an existing field. Our replacement-planning page helps separate those scopes.
What changes when an aerobic unit or filter is added?
An aerobic treatment unit supplies oxygen to support treatment organisms. That introduces mechanical equipment and continuing service needs. A media filter provides treatment through a selected medium; for example, a recirculating sand filter returns part of the flow through its treatment process. Each still needs an approved destination for the treated effluent. EPA aerobic-treatment description; EPA recirculating sand-filter description.
Ask whether the performance claim concerns organic matter, solids, nutrients or another parameter. Those are different claims. NSF identifies separate standards for residential treatment and nitrogen reduction, so a general certification statement should not be interpreted as proof of every possible treatment objective. NSF certification scope.
Useful proposal wording names the exact equipment and applicable approval. “Premium treatment” is not enough information to assess what is included or required.
Is every pumped system a pressure-distribution system?
A pump can move water to another component, while a designed pressure network distributes doses through the field. Ask what the pump is doing in this particular layout. EPA’s low-pressure-pipe fact sheet describes the dosing chamber, controls, alarm and distribution network as coordinated components. EPA low-pressure-pipe overview.
Drip is another dispersal arrangement. Its emitters require suitable filtration and maintenance, and the upstream treatment must match the design. Missouri DHSS explains why neglected pretreatment can allow solids to clog filters and emitters. DHSS drip operation.
A mound combines an elevated treatment profile with delivery to underlying natural soil. The complete mound footprint and the protection of that soil matter; the visible raised portion is not the only thing to show on a site plan. EPA mound-system description.
Use a component handoff check
Before accepting a design or installation proposal, make a row for each component and ask:
- What enters it, and where does its output go?
- Which part of the approved drawing identifies it?
- Does it need electricity, access or scheduled service?
- Who supplies, installs, inspects and maintains it?
- What tells the owner when attention is needed?
- Which manual and service contact will be supplied at handover?
If two proposals use different arrangements, compare complete treatment-and-dispersal chains before comparing totals. The alternative-system comparison guide provides the next decision sheet, and alternative septic planning helps prepare the property brief for a qualified local professional.