What are the signs a drain field is failing?
A field that stops absorbing water shows it in the house and in the yard. The usual signs:
- Slow drains or backups, even after the tank is pumped
- Soggy ground, standing water or sewage odor over the field
- Unusually green grass in a strip over the trenches
- Gray or black odorous liquid on the surface
Should I repair, replace or build a new drain field?
The cause decides. A field is not always dead when it slows down.
Virginia Tech notes that if clogged soil is the cause, diverting flow to a new field for 6 to 12 months may let the original recover, so it should not be dug up unless there is no room for a new one.
Fixes before replacement
- Pump the tank to clear stored solids
- Repair a tilted or damaged distribution box that sends all the flow to one trench
- Try drain field jetting when the lines are clogged but the soil still takes water
When replacement is the answer
A saturated or collapsed field, or one the soil cannot support, needs a new design. A repair permit application goes to the local health department before work starts.
Why is red clay hard on drain fields?
Much of the Virginia Piedmont is red clay. Clay absorbs water slowly, so a field in it needs more area or more careful design.
Slow absorption
Wastewater sits longer before it moves down. Heavy rain or a leaking fixture can push a marginal field into failure.
Compaction and roots
EPA warns against driving or parking on a field, because weight compacts the soil, and against planting trees or shrubs whose roots can damage pipes.
Reserve area
Virginia regulations require a reserve drain field for soils with slower percolation rates, at least half the size of the original. Ask the health department whether yours is recorded and where it sits.
How are drain fields permitted in Virginia?
Soil sets the design. VDH accepts site evaluations and designs from an Authorized On-site Soil Evaluator, or from a Professional Engineer in consultation with one. The health department issues the construction permit and inspects the work, and VDH issues an operation permit afterward.
The health department decides what your site needs, so confirm requirements with it before work is scheduled. The septic permits guide covers who to call.
Which drain field system fits my site?
EPA lists several designs, and the soil and site decide which is allowed.
- Trenches of stone or gravel, the conventional choice
- Chamber systems, a gravelless option that suits high groundwater or scarce gravel
- Pressure-dosed fields, where a pump sends effluent in small doses through narrow pipes
- Mound systems, a raised sand bed for shallow soil, high groundwater or shallow bedrock
- Drip distribution and aerobic treatment units, used for difficult sites
How does a drain field replacement go, and how long does it take?
The crew builds to the permitted layout: trenches or chambers at design depth, pipe and distribution to the field, then backfill after the health department inspects. Vehicles stay off the finished field.
The work is disruptive to the yard, so plan where equipment will travel. Permit lead time and weather set the schedule more than the digging does. Regular tank pumping protects the new field afterward.
How far out does Dunn Rite build drain fields?
Installations run up to 120 miles from Lynchburg, which includes the Roanoke Valley, the Charlottesville area and Southside. Soil changes from address to address, so every site is evaluated on its own. The drain field protection guide covers care of a new or old field.
On the job
Photos from Dunn Rite job sites.
Common questions
How do I know if my drain field has failed?
Common signs are slow drains, backups after pumping, wet or smelly ground over the field and a strip of lush grass over the trenches. A visit that checks the tank, the distribution box and the field surface confirms the cause. Several of these signs also point to a full tank or a tilted box, which cost less to fix than a field.
Can a failing drain field be repaired?
Sometimes. Pumping, distribution box repair or jetting can restore a field when the soil is still sound. A saturated or collapsed field needs replacement under a licensed design and a health department permit. Virginia Tech notes that resting a clogged field for 6 to 12 months can let it recover when there is room for a second field.
Do I need a permit to replace a drain field in Virginia?
Yes for significant repairs and replacements. VDH says they need a design by a licensed designer and a construction permit from the local health department, and the work is inspected before it is covered. Confirm with your health department before work begins, since a field dug without a permit can block a later sale.
What is a reserve drain field?
It is a reserved area set aside to hold a replacement field. In Virginia, soils with slower percolation rates require one at least half the size of the original, according to Virginia Tech. It does not have to be built at first, but it must stay clear of buildings, pools and driveways so a new field has somewhere to go.
Can I build over or plant on my drain field?
Do not build over it without checking with a designer or the permitting authority. The EPA also advises against trees, shrubs and vegetable gardens there, because roots damage pipes. Grass is the best cover. Vehicles and heavy equipment compact the soil and can crush the lines, so keep driveways and parking off the trenches.
How far will Dunn Rite travel to install a drain field?
Up to 120 miles from Lynchburg for septic installations, which reaches the Roanoke Valley, the Charlottesville area and Southside. That is wider than the 40 mile range for pumping and service. Call (434) 221-9885 with the address, since the site, the soil and the health district all affect whether and how a job is scheduled.