| System | Typical installed cost | Ongoing |
|---|---|---|
| Aerobic treatment unit (ATU) | $10,000–$20,000 | maintenance contract + air pump every 5–10 yrs |
| Mound / raised fill | $12,000–$25,000 | same as conventional |
| Drip irrigation dispersal | $12,000–$25,000 | filter and pump service |
| Low-pressure dosing | $10,000–$18,000 | pump service |
| Performance-based (engineered) | $15,000–$30,000+ | per design |
When you're required to go advanced: the county site evaluation says so. It is not a contractor upsell — the sanitarian's finding controls what can be permitted. If a contractor proposes an advanced system before the county has evaluated the site, ask why.