Septic Field Replacement
Failed drain fields diagnosed properly and rebuilt to code — from the test pit and provincial approval to the final inspection.
The disposal field — also called the drain field, leach field or septic bed — is where your septic system actually treats wastewater. The tank settles out the solids; the field spreads the liquid into the soil, which does the final cleaning. When a field stops accepting effluent, the whole system backs up, and no amount of pumping will fix it for long.
We replace failed septic fields throughout Greater Moncton and southeastern New Brunswick, and we start every job by confirming that the field is really the problem. Field replacement is one of the most important services our septic installation company provides, and the most expensive one to get wrong.
Signs your septic field is failing
- Wet, spongy or unusually green ground over the field, especially in dry weather.
- Sewage surfacing or a sewage odour in the yard over the field area.
- Slow drains and backups that return soon after the tank is pumped.
- Gurgling in the plumbing throughout the house.
- A high-water alarm on a pumped system that keeps going off.
- Water pooling in the tank's outlet at a higher level than normal when the tank is opened.
Related: septic warning signs and what each symptom means.
Make sure it is the field before you replace it
Several cheaper problems look exactly like a failed field, and we check them first:
- A failed effluent pump. On systems that pump to the field, a worn-out pump causes backups and alarms. Replacing it costs a fraction of a new field — see septic pump repair.
- A full or neglected tank. Solids carried out of an overdue tank can clog the field, but sometimes the tank is simply full.
- A blocked line or failed baffle between the house, the tank and the field.
- A failed tank with a sound field. In that case replacing the tank alone is the right fix.
If the field itself has stopped accepting effluent, a new field is the honest answer, and we will tell you so.
Why septic fields fail
Most drain fields fail slowly. Common causes include:
- Age. Even a well-maintained field eventually clogs as a biological mat builds up in the soil.
- Skipped pumping. Solids that escape a full tank seal off the soil under the field.
- Too much water. Leaking fixtures, a sump pump or roof drains tied into the system, or a house that has grown since the system was built.
- Damage. Vehicles, sheds or pools over the field crush pipes and compact the soil.
- Roots growing into the distribution pipes.
- Seasonal high water tables that saturate a field that was installed too low.
Related: disposal field questions and what you can and cannot do over a drain field.
How septic field replacement works
Assessment and test pit
We check the tank, the pump if there is one, and the lines, then dig a test pit to see the soil and the water table. That tells us what kind of field the lot can support today, which may differ from what was installed decades ago.
Design and approval
Replacing a disposal field in New Brunswick requires an application and approval from the Department of Public Safety before work starts. We prepare the design and handle the paperwork.
Building the new field
Where the lot allows, the new field is often built in a fresh area so the old one can be properly abandoned. Depending on the soil, it may be a conventional trench field, a chamber system or a raised sand field.
Connection, inspection and restoration
We connect the field to the tank, have the work inspected before it is covered, then backfill, grade and leave the site tidy.
Septic field replacement cost
The field is the most expensive part of a septic system. What you pay depends mainly on the soil, the water table, the size of the house and whether the lot needs a raised or engineered field. When the field has failed, the job is close to installing a new system, and most new systems in southeastern New Brunswick land between $15,000 and $30,000 installed.
We give free estimates, but a firm price comes after the test pit and once the Department of Public Safety approves the design. For a fuller breakdown, see septic system cost in New Brunswick.
Septic field replacement FAQ
How long does a septic field last?
Drain fields commonly last 20 to 30 years with good care. Regular pumping, sensible water use, and keeping vehicles, trees and roof water away from the field all add years.
Can a failing drain field be repaired instead of replaced?
Sometimes. A field that is stressed but not destroyed may partly recover if flow is reduced for a while, and a broken pipe or failed pump can be fixed on its own. A field whose soil is clogged generally needs replacement. Any digging within the field area needs an approval in New Brunswick.
Do I need a permit to replace a septic field?
Yes. Replacing a disposal field in New Brunswick must be done by a licensed installer with an approval from the Department of Public Safety, and the work is inspected before it is covered. See permits, fees and licensing.
Drain field replacement across southeastern NB
We replace septic fields in Moncton, Dieppe, Riverview, Shediac, Memramcook, Salisbury, Petitcodiac and the surrounding communities — see all communities we serve. Call (506) 233-6272 to describe what you are seeing, and we will tell you what to check first.
Ready to talk about your septic system?
Serving homeowners, builders, and property owners throughout Greater Moncton and southeastern New Brunswick.