Septic systems, explainedfrom the tank to the drainfield, and the permits at either end
Where wastewater goes after it leaves the house, what separates a conventional system from an alternative one under Virginia law, and which permits stand at the start and the end of the work.
Six parts, most of them out of sight
Wastewater leaves the house through a sewer line and runs into a septic tank. From the tank a conveyance line carries it to a distribution box, the box feeds header lines, and the header lines feed a set of absorption trenches in the yard. Those are the parts of a typical conventional system as the Virginia Department of Health (VDH) lists them, and once the ground is closed almost none of them can be seen from the surface.
Sewer line
Carries wastewater out of the house to the tank.
Septic tank
Receives the wastewater first; the Code lists septic tanks among treatment works.
Conveyance line
Moves effluent from the tank toward the field.
Distribution box
Splits the flow among the lines.
Header lines
Deliver the flow to the trenches.
Absorption trenches
Release the effluent into the soil.
Together the trenches form the drainfield, which the Code defines as a system installed within the soil and designed to accommodate treated sewage from a treatment works.
A conventional septic tank drainfield system is an in-ground system: the state rule places its infiltrative surface 18 inches or more below the original surface of the ground, in a natural, undisturbed soil horizon that treats and disperses the effluent. So a septic system is as much a question about the ground as about the pipe and the tank.
Eighteen inches of soil with nothing in the way
What lies under the trench decides whether it can work. For septic tank effluent, the state rule requires that the soil horizons for the 18 inches just under the installation depth show no limiting factor, and it lists bedrock, a seasonal or permanent water table, pans and other impervious strata.
Whether a site has that soil is what a soil evaluation is meant to document, and 12VAC5-610-450 treats percolation tests as only one of many criteria in that judgment. The procedure, and where a perc test fits in it, is set out in how perc tests work.
Two more rules shape the ground around the field. No structures may be placed over the subsurface absorption system, so the drainfield marks where a garage or a shed cannot go. And where the estimated or measured percolation rate exceeds 45 minutes per inch, the state requires a separate reserve area equal to 50 percent of the required absorption area; Carroll County's subdivision ordinance, as posted, asks for a 50 percent reserve on subdivision lots. Whether a lot needs a septic reserve area turns on those two rules.
Conventional and alternative are legal definitions, not styles
Virginia sorts onsite systems by statute, and the line between the two main kinds is drawn in the Code rather than by how a system looks in the yard.
A conventional septic system, in the Code's words a conventional onsite sewage system, is one or more septic tanks with gravity, pumped or siphoned conveyance to a gravity distributed subsurface drainfield. An alternative onsite sewage system is defined by exclusion: a treatment works that is not a conventional onsite sewage system and does not result in a point source discharge.
| Conventional | Alternative | |
|---|---|---|
| Typical parts | Sewer line, septic tank, conveyance line, distribution box, header lines, absorption trenches | Sewer line, septic tank or trash tank, a treatment unit, a pump chamber, conveyance line, distribution system and absorption field |
| At the surface | Mostly not visible | Usually, but not always, some components visible |
| Upkeep in the rules | The owner, and any later owner, maintains, repairs or replaces a system that ceases to operate as the operation permit defines | The owner must have an operator operate and maintain it, visit it at the required frequency and collect any required samples |
Owning an alternative system brings duties a conventional one does not, beginning with the licensed operator, and those are laid out in what an alternative septic system involves.
A permit to build the system and a separate one to use it
No person or owner may construct, operate, expand or modify a sewage disposal system in Virginia without a written permit from the State Health Commissioner. For a new system that means two permits, issued at two different moments.
The construction permit
Authorizes building or modifying the system. The Commissioner issues it, but every request goes first to the district or local health department, which implements and enforces the rules.
The installation
The system goes into the ground as permitted. The statute makes it the landowner's responsibility to see that the system is properly located as permitted.
The operation permit
A system built after the regulations took effect may not be operated without a separate written operation permit that authorizes its use.
The request does not arrive alone. Beginning August 11, 2019, applications have needed supporting work from a licensed private sector consultant, the license coming through the Department of Professional and Occupational Regulation (DPOR), and VDH's own evaluation and design services are limited to owners whose petition meets a means test or VDH's hardship guidelines. The Mount Rogers Health District's page also describes direct design services in Wythe County; the Wythe County Health Department can confirm how that applies to a given lot.
Carroll, Grayson and Wythe counties and the City of Galax file with health departments in the Mount Rogers Health District; Floyd, Montgomery and Pulaski counties are in the New River Health District.
The county's building permit waits on the health department
The septic permit is not a county permit, but by statute the county's building permit still waits on the health side.
No county, city, town, or employee thereof shall issue a permit for a building designed for human occupancy without the prior written authorization of the Commissioner or his agent.
Va. Code 32.1-165
The same section says when that authorization comes: on a finding that safe, adequate and proper sewage treatment is or will be made available to the building, or on a finding that the Review Board has approved issuing the permit. On a lot with no public sewer, that finding rests on the sewage system proposed for it, which is why the health department's answer comes ahead of the county building permit. Wythe County's building permit page states the order for a single-family dwelling: a septic permit before the building permit.
The septic permit is one of several a new house needs, and the full list sits in the permits you need to build a house in Virginia. A buyer who plans a house on the lot can find a builder once the septic question has an answer.
Whose name goes on which piece of paper
The record behind a septic system is written by licensed people, and each document has a particular kind of license behind it.
- Onsite soil evaluator. VDH accepts private evaluations for septic permit applications only from licensed onsite soil evaluators.
- Certifying engineer or evaluator. Where a construction permit rests on a design certified by a professional engineer or an onsite soil evaluator, that professional inspects the system at installation and reports to VDH.
- Operator. VDH says all operation and maintenance of an alternative system must be done by an operator licensed through DPOR, with an inspection at least annually.
- The local health department. Takes every request first, acts on the private evaluation and design submitted with it, and handles the permits the Commissioner issues.
A name on a report can be checked in DPOR's license search, which is where VDH sends owners instead of endorsing any provider.
The repair duty belongs to whoever owns it next
An operation permit is permission to use the system, not a promise about it. The regulation says issuing one does not guarantee the system will function for any specified period of time, and it puts maintaining, repairing or replacing a system that ceases to operate as the operation permit defines on the owner or any subsequent owner.
For an ordinary household system, VDH's inspection, pumping and lifespan figures are guidance rather than rule, and they are collected in the conventional septic system glossary entry. What the no-guarantee rule means when a house changes hands is taken up in whether a well and septic hurt resale.
An alternative system carries written duties on top of that, among them keeping the operator's log and the operation and maintenance manual on the property and making a reasonable effort to pass both to any future owner. When the property sells, whether anyone inspects the system is a separate question, taken up in whether you need a septic inspection to sell.
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Good questions, straight answers.
Who inspects a new septic system when it goes in?
Where the construction permit rests on an evaluation and design certified by a licensed professional engineer or onsite soil evaluator, Va. Code 32.1-164.1 has that certifying professional inspect the system at the time of installation and send an inspection report to VDH. Separately, Va. Code 32.1-164 makes it the landowner's responsibility to ensure the system is properly located as permitted. Questions about a particular installation go to the local health department.
Does expanding or changing an existing septic system need a permit?
Yes. Virginia's onsite sewage regulation says no person or owner may construct, operate, expand or modify a sewage disposal system without a written permit from the State Health Commissioner, and a construction permit is what authorizes a modification. The request goes first to the local health department, and beginning August 11, 2019, applications have needed supporting work from a licensed private sector consultant unless VDH approves a petition for its own services. What a given change requires is the health department's call.
Can the county issue a building permit before the septic paperwork is done?
Not for a building designed for human occupancy. Va. Code 32.1-165 bars a county, city or town from issuing that permit without the prior written authorization of the State Health Commissioner or his agent, given on a finding that safe, adequate and proper sewage treatment is or will be made available, or on Review Board approval. Wythe County's building permit page, for example, requires a septic permit before a building permit for a single-family dwelling.
Where this page's facts come from
Every rule, office and figure above traces to one of these. Rules change; check the office before you act on one.
- Va. Code 32.1-163: definitions of conventional and alternative onsite sewage systems, subsurface drainfield and treatment works Virginia General Assembly
- Va. Code 32.1-165: no building permit without the Commissioner's prior written authorization Virginia General Assembly
- Va. Code 32.1-163.4: private evaluations accepted only from licensed onsite soil evaluators Virginia General Assembly
- Va. Code 32.1-164.1: the certifying professional inspects the system at installation Virginia General Assembly
- Va. Code 32.1-164: the landowner's responsibility to locate the system as permitted Virginia General Assembly
- 12VAC5-610-240: construction and operation permits required Virginia Department of Health
- 12VAC5-610-250: construction permit requests directed first to the local health department Virginia Department of Health
- 12VAC5-610-340: an operation permit is no guarantee, and the owner's duty to maintain Virginia Department of Health
- 12VAC5-610-450: soil evaluations, and the percolation test as one of many criteria Virginia Department of Health
- 12VAC5-610-594: in-ground systems and the 18 inches below the installation depth Virginia Department of Health
- 12VAC5-610-700: no structures over the subsurface soil absorption system Virginia Department of Health
- 12VAC5-610-710: the reserve area where the percolation rate exceeds 45 minutes per inch Virginia Department of Health
- 12VAC5-613-140: owner responsibilities for an alternative onsite sewage system Virginia Department of Health
- Onsite sewage system owner responsibilities Virginia Department of Health
- Alternative onsite sewage system operation and maintenance FAQs Virginia Department of Health
- Have you considered using the private sector? (licensed private sector work since August 11, 2019) Virginia Department of Health
- Septic system and private well service providers Virginia Department of Health
- Mount Rogers Health District: environmental health Virginia Department of Health
- Mount Rogers Health District locations Virginia Department of Health
- New River Health District locations Virginia Department of Health
- Building Permit Requirements Wythe County, Virginia
- Subdivision Ordinance, April 14, 2014 (reserve area for drainage fields) Carroll County, Virginia