Sourced from 12VAC5-613 (Regulations for Alternative Onsite Sewage Systems), §§ 32.1-163.5 and 15.2-2157 of the Code of Virginia — last checked August 2026.
What Makes a System “Alternative”
A conventional system is a septic tank and a soil drainfield. An AOSS adds treatment — aerobic units, sand filters, drip dispersal, or other technologies — usually because the site can’t support a conventional design.
Virginia regulates these under a separate chapter because the performance requirements in 12VAC5-610 were inadequate for them. The 2011 rulemaking cited three reasons: those inadequate requirements, statutory changes in 2008 (§ 32.1-163.5) allowing professional engineers to design AOSS outside the standard regulations, and the fact that proper operation and maintenance is essential for an AOSS to function as designed.
The Land Records Requirement
This makes the AOSS a matter of public record attached to the property itself. It runs with the land, and it will surface in a title search.
For a buyer, that’s useful — the system’s existence can’t be quietly omitted. For an owner, it means the obligations attached to the permit follow the property rather than the person.
VDH also will not issue the operation permit until the owner has established a relationship with a licensed operator and provided that operator’s name and license number to the local health department.
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The December 7, 2011 Dividing Line
This is the detail AOSS owners most need and are least likely to know. Three separate requirements turn on when your application was filed.
| Requirement | Applies to |
|---|---|
| Operation & maintenance requirements (Part III) | All AOSSs, including those applied for before Dec 7, 2011 |
| Renewable operation permits | Only applications filed on or after Dec 7, 2011 |
| Laboratory sampling requirements | Only applications filed on or after Dec 7, 2011 |
So an older AOSS carries full operation and maintenance duties, but not the renewable-permit or lab-sampling regime. A newer one carries all three. If you don’t know which side of that date your system falls on, your local health department does.
Operator Visits Are Not Optional
Under 12VAC5-613-150, the owner of each AOSS with flows up to 40,000 gallons per day must have the system visited by a licensed operator according to Table 4 of the chapter. Systems above 40,000 GPD must be attended by a licensed operator under the Sewage Collection and Treatment Regulations.
This is a recurring cost of ownership that installation quotes don’t include, and it’s worth budgeting for from the start.
The O&M Manual and Log
Two documents exist for your system, and you’re entitled to both.
The O&M manual. Under 12VAC5-613-170, before an operation permit issues the owner must submit a manual to the local health department for approval. The regulation requires it be “easily understood by any potential owner” and cover treatment unit capacity, installation depth, pump operating conditions, a component list, a dimensioned site layout, sampling locations, replacement-part contacts, control functions, all operation and maintenance and sampling and inspection schedules, the performance data reporting schedule, and the design limits of the system.
The operator’s log. Under 12VAC5-613-140, the owner must keep a copy of the log the operator provides, on the property, in electronic or hard copy form; make it available to VDH on request; and make a reasonable effort to transfer the log to any future owner.
If you’re buying an AOSS property, ask for both. If you’re selling one, the log transfer is an obligation, not a courtesy.
Performance Standards
AOSS requirements are measurably stricter than conventional systems.
Fecal coliform must not exceed 2.2 cfu/100 ml at the lower vertical limit of the project area boundary.
Large AOSS must comply with a total nitrogen limit of 5 mg/l at the project area boundary, demonstrated before permit issuance through modeling or calculation.
Direct dispersal to groundwater in the Chesapeake Bay Watershed is stricter still: total nitrogen at or below 3 mg/l and total phosphorus at or below 0.3 mg/l.
All small AOSSs within the Chesapeake Bay Watershed must reduce nutrient loads. And under 12VAC5-613-190, an AOSS inside a Chesapeake Bay Preservation Area must also comply with local CBPA ordinances — including the five-year pump-out requirement.
One Protection Worth Knowing
Enforcement powers are real — under 12VAC5-613-70, VDH may void a construction or operation permit, impose civil penalties, or pursue criminal prosecution under § 32.1-27.
But the same section contains a genuine protection for owners. Except where there is additional evidence that the system has failed a performance requirement, or a licensed operator has reported it cannot be returned to normal function through routine maintenance, the department shall not rely solely on the results of an individual grab sample to establish a violation.
One bad sample, on its own, is not a violation.
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Frequently Asked Questions
What is an alternative onsite sewage system in Virginia?
A system using treatment beyond a conventional septic tank and drainfield, regulated under 12VAC5-613. They are typically required where soil conditions or vertical separation will not support a conventional system.
Is an AOSS recorded on my property title?
Effectively yes. Under 12VAC5-613-60, VDH will not issue an operation permit until the owner records an instrument complying with section 15.2-2157 E of the Code of Virginia in circuit court land records. It runs with the land and appears in a title search.
Do I need an operator for my alternative system?
Yes. VDH will not issue an operation permit until you have established a relationship with a licensed operator, and under 12VAC5-613-150 the operator must visit on a schedule set by Table 4 of the chapter.
Why does December 7, 2011 matter for my AOSS?
Three requirements turn on it. Operation and maintenance requirements apply to all AOSSs including older ones, but renewable operation permits and laboratory sampling requirements apply only to applications filed on or after that date.
What documents should I have for my AOSS?
An approved O&M manual, required under 12VAC5-613-170 to be understandable to any potential owner, and the operator log, which under 12VAC5-613-140 you must keep on the property and make a reasonable effort to transfer to any future owner.