Indiana · 410 IAC 6-8.3-60
Septic system requirements in Indiana
Tank sizes, drainfield rules, setbacks, permits, and real costs — pulled from Indiana's own code rather than a national average.
- 3-bedroom tank
- 1,000 gal
- Design flow
- 150 gpd/BR
- Typical install
- $8,000–$21,000
- Permit fee
- $150–$600
- Well setback
- 50 ft
- Permitted by
- County / local
Septic tank sizes required in Indiana
Indiana sizes systems on a design flow of 150 gallons per day per bedroom. The tank must meet both the bedroom table below and a 2× daily-flow detention requirement — whichever produces the larger number governs.
| Bedrooms | Design flow | Code minimum | Recommended |
|---|---|---|---|
| 1 bedroom | 150 gpd | 750 gal | 750 gal |
| 2 bedrooms | 300 gpd | 750 gal | 750 gal |
| 3 bedrooms | 450 gpd | 1,000 gal | 1,000 gal |
| 4 bedrooms | 600 gpd | 1,250 gal | 1,250 gal |
| 5 bedrooms | 750 gpd | 1,500 gal | 1,500 gal |
| 6 bedrooms | 900 gpd | 1,800 gal | 2,000 gal |
Source: 410 IAC 6-8.3-60. The recommended column rounds the governing requirement up to a tank size manufacturers actually stock.Run your own numbers →
Drainfield size and cost by soil type
For a three-bedroom home in Indiana at 450 gpd. This single table explains most of the variation between quotes — the area scales inversely with how fast your soil accepts water, and the drainfield is the largest line item in the job.
| Soil | Loading rate | Absorption area | With reserve | Typical total install |
|---|---|---|---|---|
| Medium sand | 0.8 gpd/ft² | 563 ft² | 1,126 ft² | $10,800 |
| Sandy loam | 0.5 gpd/ft² | 900 ft² | 1,800 ft² | $13,800 |
| Loam | 0.4 gpd/ft² | 1,125 ft² | 2,250 ft² | $15,700 |
| Silt loam | 0.3 gpd/ft² | 1,500 ft² | 3,000 ft² | $18,900 |
| Clay loam | 0.2 gpd/ft² | 2,250 ft² | 4,500 ft² | $25,400 |
Estimates use Indiana's cost index of 0.96× the national average. Build a line-item estimate →
Permits and who issues them
Local health departments issue permits under 410 IAC 6-8.3, the statewide residential on-site sewage rule.
| Permit required | Yes |
|---|---|
| Typical fee | $150 – $600 |
| Soil evaluation | Required before permit |
| Licensed installer | Not required statewide |
| Turnaround | 2–4 weeks |
| Ongoing inspection | Not mandated statewide |
| Reserve area | 100% replacement area required |
Minimum setback distances
Measured horizontally from the drainfield unless noted. Local rules are frequently stricter, and on a small lot these numbers — not the soil — often decide the layout.
| Private water well | 50 ft |
|---|---|
| Well (septic tank) | 25 ft |
| Property line | 5 ft |
| Surface water | 50 ft |
| Building foundation | 10 ft |
Regulatory contact
Indiana Department of Health — Onsite Sewage Systems Program
www.in.gov · 317-233-7177
What makes septic hard in Indiana
Most of the state is glacial till with dense, slowly permeable subsoil, so elevated sand mounds are extremely common.
Southern Indiana karst means sinkholes and fast, untreated pathways to groundwater.
High seasonal water tables in the northern lake country restrict conventional trenches.
Things that catch people out
- Indiana adds 300 gallons per bedroom above five, not the 250 that most states use.
- A soil scientist's report is effectively mandatory — a percolation test alone will not satisfy most Indiana health departments.
Indiana septic questions
What size septic tank do I need in Indiana?
A three-bedroom home in Indiana requires a minimum 1,000 gallon tank under 410 IAC 6-8.3-60. Design flow is 150 gallons per day per bedroom, and the tank must also hold 2 times daily flow, so the practical recommendation is 1,000 gallons.
Do I need a permit for a septic system in Indiana?
Yes. Local health departments issue permits under 410 IAC 6-8.3, the statewide residential on-site sewage rule. Fees typically run $150 to $600, with a turnaround of about 2–4 weeks. A soil evaluation or percolation test is required before a permit is issued.
How much does a septic system cost in Indiana?
A conventional system for a three-bedroom home typically runs $8,000 to $21,000 installed. Soil quality moves this more than anything else — on tight clay requiring a mound, budget two to three times the low end.
How far must a Indiana drainfield be from a well?
50 feet from a private water well, with the septic tank itself allowed at 25 feet. Local rules can be stricter.
Sources
Every figure on this page traces to one of these documents.
- 410 IAC 6-8.3-60 — Septic tanks: general requirements · verified 2026-09-18
- 410 IAC 6-8.3 — Residential On-Site Sewage Systems Rule · verified 2026-09-18