Arkansas · Act 402 of 1977 · Arkansas Department of Health
Arkansas uses a Designated Representative system — a licensed professional who both evaluates your soil and designs your septic system. In the Ozark and Ouachita regions, fractured limestone and karst terrain rule out conventional drainfields entirely, making site evaluation the most important step before any design begins.
Minimum tank
For standard residential dwellings. DR may specify larger based on soil evaluation and bedroom count.
Two permits required
Both issued by local county health unit under ADH oversight. No work begins before construction permit.
Governing law
Arkansas Department of Health Onsite Wastewater Program. County sanitarians issue permits locally.
Ozark and Ouachita regions: thin rocky soil over fractured limestone — your DR determines whether conventional absorption is feasible. Delta region: heavy clay. Your DR's soil evaluation is the definitive answer for your parcel.
| Dwelling | Design flow | Minimum tank | With garbage disposal |
|---|---|---|---|
| 1 bedroom | 150 gpd | 1,000 gal | 1,250 gal |
| 2 bedrooms | 300 gpd | 1,000 gal | 1,250 gal |
| 3 bedrooms | 450 gpd | 1,000 gal | 1,250 gal |
| 4 bedrooms | 600 gpd | 1,250 gal | 1,500 gal |
| 5 bedrooms | 750 gpd | 1,500 gal | 1,750 gal |
| 6 bedrooms | 900 gpd | 2,000 gal | 2,250 gal |
Tank materials approved in Arkansas: concrete, fiberglass, and polyethylene — all must be watertight and corrosion-resistant per ADH requirements.
Next step: Use the installation cost estimator to see total Arkansas system costs, or check perc test costs in Arkansas — DR evaluations typically run $500 to $1,500.
Arkansas unique system
Like Maine's Licensed Site Evaluator, Arkansas uses a single licensed professional who handles both soil evaluation and system design. No DR means no permit.
What a DR does
The Designated Representative conducts a soil morphology evaluation on your site, determines what system type is feasible, sizes the components, and submits the design to the local county health unit for permitting. This is the first professional you hire — before an installer, before ordering any materials.
Who qualifies as a DR
Qualified DRs under Act 402 include: Registered Professional Engineers, Registered Professional Land Surveyors, Registered Professional Sanitarians, and Licensed Master Plumbers. Individuals with soil science education and equivalent experience may be approved on a case-by-case basis by ADH.
Finding a DR
Arkansas Department of Health maintains a searchable database of licensed Designated Representatives. Search by "Designated Representative" license type to find a DR in your county. Local DRs familiar with your county sanitarian and regional soil conditions are worth seeking out — they know what the local office expects in a permit application.
DR exam
The ADH administers the DR licensing examination nine times per year, January through September. Exam dates are posted on the ADH Training and Examination page. The same examination applies to anyone seeking DR status — including engineers and sanitarians who must pass it to practice in Arkansas. This is the same exam pathway as the installer license, administered separately.
Arkansas geology
Arkansas's geology splits into three distinct zones. Each one creates a fundamentally different septic challenge, and the system type that works in one zone typically cannot be used in another.
Ozark Plateau
Northern and western Arkansas — Benton, Carroll, Boone, Marion, Stone, and Searcy counties — sit on the Ozark Plateau, where limestone and dolomite bedrock has been dissolved and fractured over millennia into karst terrain. Sinkholes, caves, and springs characterize this landscape. Conventional drainfield trenches cannot be used because effluent reaches fractured bedrock without adequate soil treatment and flows directly into groundwater. The ADH requires secondary treatment systems here: aerobic treatment units, sand filters, or mound systems that treat effluent thoroughly before it contacts the ground.
Ouachita Mountains
The Ouachita range in west-central Arkansas — Polk, Montgomery, Garland, and surrounding counties — has thin soil over sandstone and shale bedrock. Unlike karst limestone, the Ouachita bedrock is not soluble and does not form caves, but shallow depth to rock still limits trench depth. Mound systems and shallow-trench designs with secondary treatment are common answers in this terrain. Depth to bedrock varies significantly within short distances, making site-by-site evaluation essential.
Mississippi Delta
Eastern Arkansas — the Delta counties along the Mississippi River — has deep alluvial clay soils with very slow percolation rates. Bedrock is not the problem here; absorption is. Heavy clay requires large drainfield areas to handle the same daily flow that sandy soil absorbs in a fraction of the space. Systems in Delta counties tend to be larger and more expensive than the same bedroom count in central Arkansas, due to the required field size.
| Region | Geology | Conventional field? | Typical system | Key counties |
|---|---|---|---|---|
| Ozark Plateau | Karst limestone, dolomite | Not permitted in karst areas | Aerobic unit, sand filter, mound | Benton, Carroll, Boone, Marion |
| Ouachita Mountains | Sandstone, shale, thin soil | Limited — depth to rock constrains | Mound, shallow trench | Polk, Montgomery, Garland |
| Arkansas River Valley | Mixed alluvial, variable | Often yes | Conventional gravity | Pope, Johnson, Sebastian |
| Central uplands | Mixed, moderate depth | Usually yes | Conventional gravity | Pulaski, Faulkner, Saline |
| Mississippi Delta | Deep alluvial clay | Yes but large fields | Conventional, large field | Crittenden, Mississippi, Lee |
Installation cost
Arkansas has significant cost variation driven almost entirely by geology — karst and rocky terrain push costs well above the Delta and central region baseline.
| Region | System type | Typical cost | Main driver |
|---|---|---|---|
| Central Arkansas Pulaski, Faulkner, Saline |
Conventional gravity | $6,000 – $11,000 | Good soil access, competitive contractor market |
| Arkansas River Valley Pope, Johnson, Sebastian |
Conventional gravity | $7,000 – $13,000 | Variable soil, moderate terrain |
| Ozark Plateau Benton, Carroll, Boone, Marion |
Aerobic unit, sand filter, mound | $12,000 – $25,000 | Karst terrain, alternative system required |
| Ouachita Mountains Polk, Montgomery, Garland |
Mound or shallow trench | $10,000 – $20,000 | Shallow bedrock, limited depth |
| Mississippi Delta Crittenden, Mississippi, Lee |
Conventional, large field | $8,000 – $15,000 | Clay soils require large absorption area |
| DR evaluation fee | — | $500 – $1,500 | Soil evaluation + system design |
| Pump-out service | — | $200 – $450 | Tank size, access, county location |
Arkansas requires two permits — construction and operation — both from the local county health unit. The Designated Representative handles the design submission; the county sanitarian reviews and issues permits.
Your first call. The DR conducts the soil morphology evaluation on your specific site, determines what system type ADH will approve, sizes the tank and drainfield, and prepares the permit application. Find a licensed DR through the ADH licensee database. Cost: $500 to $1,500 depending on site complexity and location.
The DR digs test pits and reads the soil profile: texture, structure, color, depth to restrictive layers (rock or water table), and percolation characteristics. In Ozark karst areas, this step determines whether any soil-absorption system is feasible at all. If the site is in a karst zone, the DR must document why a conventional system is not feasible and propose an alternative — this statement is required by ADH for alternative system applications.
The DR submits the design to the local county health unit. The county sanitarian reviews for compliance with ADH rules and issues the construction permit. No excavation or installation may begin before this permit is in hand. Review times vary by county — rural counties may take longer during spring and summer peak season.
Arkansas requires a licensed Advanced Septic Installer for all installations. Homeowners who want to install their own system must pass the same ADH licensing examination — administered nine times per year — and register with the state before beginning work. For alternative systems in karst areas, homeowner installation is not permitted under any circumstances; a licensed installer is required.
After installation, the county sanitarian inspects before backfill. Once the system passes inspection, the operation permit is issued. Both permits must be in hand before the system is put into use. Inspection before backfill is non-negotiable — burying the system without inspection requires excavating at the owner's expense.
This is one of the most searched questions about Arkansas septic systems. The answer is limited. A homeowner can technically install a conventional system on their own property — but only after passing the ADH licensing examination and registering with the state, the same path a professional installer takes. For any alternative system (required throughout the Ozark karst region), homeowner installation is explicitly prohibited. A licensed Advanced Septic Installer must perform the work.
In practice, very few homeowners pursue self-installation because the licensing process requires passing a technical examination covering soils, hydraulics, and system design. The cost savings rarely justify the time and risk.
Arkansas requires separate licenses for different septic roles under Act 402:
| License type | Who needs it | Exam frequency |
|---|---|---|
| Designated Representative | Anyone evaluating soil and designing systems | 9 times/year (Jan–Sep) |
| Advanced Septic Installer | Anyone installing systems | 9 times/year |
| Septic Tank Cleaner | Anyone pumping tanks or holding tanks | 10 times/year (Jan–Oct) |
All exam dates are posted on the ADH Training and Examination page. License searches for DRs and installers are available through the ADH online database.
Verify before you build. Requirements compiled from Arkansas Act 402 of 1977 and ADH Onsite Wastewater Program rules for planning purposes. Local county sanitarians set the practical standard for your parcel. Confirm all requirements with your county health unit before designing or ordering equipment. Official resource: healthy.arkansas.gov — Onsite Wastewater.
Arkansas questions
Next steps
Cost estimator
Get a detailed Arkansas cost estimate by bedroom count, soil type, and system type.
DR evaluation cost
DR evaluations run $500 to $1,500 in Arkansas. See how that compares nationally.
Pump schedule
Find your service interval by household size and tank capacity.
Replacement cost
Replacement costs more than new installation — get an Arkansas-specific estimate.
Drainfield size
Calculate absorption area by soil type — especially useful for Delta clay sites.
Local quotes
Get free quotes from licensed Arkansas septic contractors in your county.
Official resources
Arkansas Department of Health
Act 402 of 1977 — Onsite Wastewater Rules
DR and installer licensee database
Exam dates and training materials
Permit forms: EHP-6, EHP-19, EHP-19N
County health units
Construction and operation permits are issued by local county sanitarians, not ADH centrally. Contact your county health unit for local permit requirements, review timelines, and any county-specific standards that exceed the ADH baseline.
Nearby states