Arkansas · Ark. State Board of Health Rules
Septic system requirements in Arkansas
Tank sizes, drainfield rules, setbacks, permits, and real costs — pulled from Arkansas's own code rather than a national average.
- 3-bedroom tank
- 1,000 gal
- Design flow
- 150 gpd/BR
- Typical install
- $5,000–$13,000
- Permit fee
- $150–$400
- Well setback
- 100 ft
- Permitted by
- State agency
Septic tank sizes required in Arkansas
Arkansas 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 | 1,000 gal | 1,000 gal |
| 2 bedrooms | 300 gpd | 1,000 gal | 1,000 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 | 1,750 gal | 2,000 gal |
Source: Ark. State Board of Health Rules. 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 Arkansas 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 | $9,400 |
| Sandy loam | 0.5 gpd/ft² | 900 ft² | 1,800 ft² | $12,000 |
| Loam | 0.4 gpd/ft² | 1,125 ft² | 2,250 ft² | $13,700 |
| Silt loam | 0.3 gpd/ft² | 1,500 ft² | 3,000 ft² | $16,500 |
| Clay loam | 0.2 gpd/ft² | 2,250 ft² | 4,500 ft² | $22,200 |
Estimates use Arkansas's cost index of 0.84× the national average. Build a line-item estimate →
Permits and who issues them
The Arkansas Department of Health runs a single statewide program through its county health units; Designated Representatives do the soil work.
| Permit required | Yes |
|---|---|
| Typical fee | $150 – $400 |
| Soil evaluation | Required before permit |
| Licensed installer | Required |
| 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 | 100 ft |
|---|---|
| Well (septic tank) | 50 ft |
| Property line | 5 ft |
| Surface water | 50 ft |
| Building foundation | 10 ft |
Regulatory contact
Arkansas Department of Health — Onsite Wastewater
healthy.arkansas.gov · 501-661-2171
What makes septic hard in Arkansas
The Ozark and Ouachita uplands are thin soil over fractured rock, which is the hardest combination to permit: water moves fast but there is nothing to treat it.
Delta counties sit on deep, slow clay with a high water table — the opposite problem, and the reason mound systems are common there.
Karst terrain in the north means sinkholes and rapid groundwater connection; expect enhanced treatment requirements.
Things that catch people out
- A 100-foot well setback is strictly enforced and often the binding constraint on small rural lots.
- Only a licensed Designated Representative can do the soil evaluation — a contractor's opinion will not get a permit issued.
Arkansas septic questions
What size septic tank do I need in Arkansas?
A three-bedroom home in Arkansas requires a minimum 1,000 gallon tank under Ark. State Board of Health Rules. 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 Arkansas?
Yes. The Arkansas Department of Health runs a single statewide program through its county health units; Designated Representatives do the soil work. Fees typically run $150 to $400, 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 Arkansas?
A conventional system for a three-bedroom home typically runs $5,000 to $13,000 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 Arkansas drainfield be from a well?
100 feet from a private water well, with the septic tank itself allowed at 50 feet. Local rules can be stricter.
Sources
Every figure on this page traces to one of these documents.
- Ark. State Board of Health Rules — Rules Pertaining to Onsite Wastewater Systems · verified 2026-09-18