Building on Acreage
Most people pick the house site first, for the view or the access, and find out afterwards where the drainfield is allowed to go. On broken ground that order is expensive.
Sequence and requirements verified August 10, 2026.
On a flat, deep, well-drained parcel the order barely matters — put the house anywhere and the system will fit somewhere. That is not most of this area.
Where usable soil is patchy, the drainfield has fewer possible positions than the house does. It needs suitable ground, a full reserve area of equivalent suitable ground, separation from any well and from surface water, and trenches that run level and on contour. A house can sit on rock. A drainfield cannot.
So the sequence that saves money is to find the field first and place the house around it. That is the single most useful thing on this page.
The order that works
1. Look at the soil before anything is staked
Free, before hiring anyone: the USDA Natural Resources Conservation Service publishes soil mapping for every acre in Arkansas through its Web Soil Survey, searchable by address or by drawing a boundary. It will not decide the design, but it will tell you roughly which parts of a parcel are worth walking and which are probably not. What the soil names mean here is a separate subject with its own page.
2. Get the soil evaluation, then design the site plan
A licensed Designated Representative opens soil pits and reads the profile. The output is not a pass or a fail; it is the information needed to design a system the ground will support. What that evidence is and who can produce it is covered separately.
The practical instruction is this: ask for the field location and the reserve area to be identified before the house footprint is fixed. A Designated Representative asked early can usually say “the field goes here, so keep the house upslope of it and the well over there.” Asked late, the same person can only tell you what the remaining options cost.
3. Place the well, the house and the drive around the field
Three separations compete for the same ground on a rural build:
- 100 feet from a domestic water well to any part of the sewage system.
- 100 feet from the high water mark of streams and lakes; 50 feet from a pond on the same property; 300 feet from a spring used for domestic water.
- 10 feet from the dwelling, from property lines, and from water service lines, on a permitted system.
The well is the one people forget until the driller is booked. On a parcel with one good field area, the well has to go a hundred feet from it and still reach water — and both of those constraints are easier to satisfy on paper than after a house pad is cut.
The reserve area is real ground, and it has to stay untouched
Arkansas requires both a primary and a secondary absorption area, each sized on natural soil data, and good management practices may not be substituted to reduce the minimum lot size.
On a new build this is not an abstraction — it is roughly twice the suitable ground a single field would need, found and protected before construction traffic starts. The reserve is only useful if the soil in it stays undisturbed, and a build generates exactly the things that ruin it: material stacks, spoil piles, a temporary turnaround for concrete trucks, a driveway routed the short way.
Mark the reserve on the site plan and treat it as a no-go area for the duration. It costs nothing during the build and it is close to unrecoverable afterwards.
What compaction actually does
The same principle applies to the field itself during installation. The Department of Health teaches installers a field check for soil too wet to work — roll it between thumb and forefinger, and if it ribbons, the lateral field cannot go in that day. Working wet ground smears the trench sidewalls and compacts the soil, permanently reducing absorption.
On a build with a schedule, that is the moment where pressure gets applied to a crew. An installer who stops is protecting the system.
Then the paperwork, in its own order
Once the design exists, the sequence is fixed and short. Full detail, including the forms by number and the county contacts, is on the permit process page; what matters for a build schedule is:
- The Designated Representative submits the permit application — not the homeowner, not the builder.
- The permit is valid one year. On a build that slips, that clock matters.
- No changes without the Designated Representative's authorisation. A late decision to add a bedroom is a design change: tank sizing runs on bedroom count, at a minimum of 1,000 gallons through three bedrooms and 1,250 at four.
- 24 hours' notice to the county before installation begins.
- A licensed installer on site throughout, and the closing paperwork filed within five working days.
Two situations change this. A single residence on ten or more acres may be exempt from the permit itself if every component sits more than 200 feet from every property line including roads — the conditions and the geometry are set out separately. And a design that discharges to the surface brings in a second agency with its own 30-day lead time, covered on the same page.
The bedroom-count trap on a custom build
Tank size is set by bedrooms, not by square footage or by household size. A study, a bonus room over the garage or a finished basement room with a closet can be counted as a bedroom by the design. Deciding that late, after the permit is issued, is a change requiring authorisation rather than a note to the plumber.
Worth settling the room count with the Designated Representative before the permit goes in, not during framing.
Common questions
The soil evaluation. The drainfield needs suitable ground and a reserve area of equivalent suitable ground, and on broken terrain those may exist in only one part of a parcel. Fixing the house position first can leave the system with nowhere to go, or force a more expensive engineered design that a different house position would have avoided.
One hundred feet from a domestic water well. Other separations apply from surface water: 100 feet from the high water mark of streams and lakes, 50 feet from a pond on the same property, 100 feet from a pond on other property, and 300 feet from any spring used as a source of domestic water. A well and a drainfield both compete for the same buildable ground, which is why they are planned together.
Yes. Arkansas rules require every lot to have both a primary and a secondary absorption area, each sized on natural soil data. Good management practices may not be substituted to reduce the minimum lot size. In practice this means finding roughly twice the suitable ground a single field would need, and protecting the reserve from driveways, outbuildings and compaction.
It should not be. The reserve area only works if the soil in it stays undisturbed, and compaction from traffic or construction reduces how much water the ground can absorb. Marking the reserve on the site plan early is the practical way to keep it from being paved, built on or used for material storage during the build.
One year without revalidation, which matters on a build that may slip. Within that year no changes or substitutions may be made to the permitted design without the authorisation of the Designated Representative who submitted it, so a late change to house size or position is a design question rather than a field decision.
Planning a build and want the field located before the house is staked?
Send the property details and a licensed local professional can take it from there.
Sources
- Arkansas Department of Health, Rules Pertaining to Onsite Wastewater Systems, and departmental installer training materials — primary and secondary absorption area requirement, well and surface water setbacks, dwelling and property line setbacks, trenches on contour, tank sizing by bedroom count, permit validity and change authorisation, 24-hour notice, installer presence, closing paperwork, and the wet-soil field check. Verified August 10, 2026.
- USDA Natural Resources Conservation Service, Web Soil Survey — public soil mapping by address or boundary.
Where a field and a reserve area can go is a question about a specific parcel and its soil profile. Nothing here substitutes for an evaluation carried out on the ground by a licensed Designated Representative.