The average cost to replace a septic tank and drain field is around $6,000
Replacing a septic tank and drain or leach field can range anywhere from $2,000 for a tiny backyard to $20,000 or more if you have a high-end system and a lot of land. Drain fields are one of the most crucial parts of a septic tank system, and when one goes, your backyard can flood and become pretty stinky.
Ultimately, the cost of replacing a septic tank and drain field depends on the size of the field and what type of septic system you have.
| Low Cost | Average Cost | High Cost |
|---|---|---|
| $2,000 | $6,000 | $20,000 |
Septic Tank and Drain Field Replacement Cost Breakdown
It may not be the most glamorous topic, but it’s an essential one. Learn septic tank and drain field replacement prices below so you can budget for potential costs. Contact a local septic tank installation company for a more accurate quote based on your specific needs.
Septic Tank and Drain Field Size
In general, larger drain fields cost more to replace than smaller ones. That's because large areas require more time and labor to cover. Large areas also require large septic tanks, which are heavier and more difficult to install and maneuver than small tanks, further driving up costs.
Septic Tank and Drain Field Type
Different septic systems require different drain field types to function. The type of drain field you have can affect costs. For instance, anaerobic septic system drain fields typically cost $5,000 to replace, while mound septic drain fields cost an average of $12,000.
Location and Accessibility
If your septic system and drain field are in a tough-to-reach location, you can expect to pay more to replace it. Locations that aren't easy to access will require more time, labor, and potentially equipment, to get the job done, which increases costs.
Perc Testing
Perc testing is required before replacing a leach field. These tests check the drain field’s ground for its ability to absorb water and filter it. If you’ve been using your drain field for several decades, there’s a chance that your current field may no longer be suitable, and you might need to move it or upgrade your system. The average cost of perc testing is around $1,000.
Labor
Installing a septic system in a yard is one of the most labor-intensive projects out there. It requires a lot of digging and other labor to get done. Labor will typically make up 60% of the project’s total cost, bringing the average to around $3,600.
Permits
To ensure you don’t accidentally dig off your property or into the city's power lines or city pipes, you’ll need to file a permit ahead of time. Permits for replacing a drainage field will cost anywhere from $400 to $2,000, depending on your local government regulations.
Drain or Leach Field Replacement Cost by Type
Not all septic systems are a simple tank underneath the ground with a drain field attached. Technology offers many ways to hide the leach field and disperse wastewater.
Mound Septic System Drain Field Cost
Mound septic system drain fields are typically on the high end, as these drain fields are not buried in the soil. Instead, you need to use an elevated mound of sand to cover the piping. Because this often requires pumping the sand uphill and then creating a mound to put the pipes in, the average cost to replace a mound septic system drain field is around $12,000.
Evapotranspiration Septic System Drain Field Cost
People living in dry, arid climates often benefit from evapotranspiration septic systems. These systems allow the water to evaporate through an open-air tank rather than running into a water table. Evapotranspiration septic system drain fields cost, on average, around $8,000.
Anaerobic Septic System Drain Field Cost
Anaerobic septic systems are the most basic septic systems. This system brings waste down to the septic tank and then into the drain field. It relies on anaerobic bacteria to break down waste before continuing down the drain field to remove the anaerobic bacteria.
While simple in nature, these systems often require the most land for your drain field. These systems cost around $5,000 on average, but around $3,500 of the cost comes from the drain field system installation.
Aerobic Septic System Drain Field Cost
Aerobic septic system drain fields don’t require nearly as much land as anaerobic ones. These systems utilize an aerator and electrical circuit to continuously supply oxygen to the aerobic bacteria inside. An aerobic septic system drain field costs around $7,000 on average.
Additional Costs to Consider
Engineering and Design Fees
In some cases, you might want to consult with an engineer to optimize your septic system, especially in the case of mound systems. Engineering consultant hourly rates usually range from $125 to $200 per hour.
Inspection Costs
New septic systems require at least two professional inspections during construction to ensure the system meets safety standards. Septic system inspections cost between $200 and $900, depending on your system and municipality.
Excavation Costs
Many septic systems and drain fields require some land excavation to install. Excavation costs typically range from $1 to $5 per square foot.
Tree or Root Removal
If there are some trees and/or roots in the way, you'll likely need to pay a pro to remove them before replacing your septic tank and drain field. Tree removal costs range from $200 to $2,000 depending on the tree's size, location, and type.
Sod Installation
If you want to lay sod on top of your new drain field, you should factor sod installation costs into the total budget. Sod typically costs $0.35 to $0.85 per square foot for the materials alone. If you hire a pro to lay it for you, you can expect to pay $1 to $2 per square foot total for sod installation.
New Septic Lines Cost
Often you'll need a new septic line to connect your new septic tank to your new drain field. New septic lines usually range from $50 to $150 per linear foot to install.
Septic Aerator Installation
Septic aerators help to break down waste materials in a septic tank, which reduces the workload on your drain field. Septic aerators usually cost $200 to $600 alone. Paying a pro to install one will drive those costs up to $300 to $900.
Yard Regrading
Sometimes, replacing your septic tank and drain field can make your yard less level, in which case you might want to regrade it. Yard regrading costs between $1,000 and $3,000, on average.
Leach Field Abandonment Permit Costs
You typically need a permit to abandon a defunct leach field. Leach field abandonment regulations vary by city, but permits usually cost between $100 and $250.
Cost to Replace a Septic Tank and Drain Field Yourself
Because you’ll need to file permits and septic system replacement often requires heavy equipment, labor, expertise, and perc testing, this is not a job you should tackle yourself.
Hire a septic company to tackle it for you instead. This job requires large excavators, multiple people, and even sometimes a crane if a lot of piping is needed to complete the job.
You can also hire a septic tank cleaner in your area to keep your system maintained properly throughout each year.
Frequently Asked Questions
If you’re maintaining your septic system, your drain field should last around 20 years, on average. However, it’s important to get it inspected annually to ensure the entire system is in safe, working order. Contact a septic maintenance company in your area for a quote.
If you no longer have the space available for a large drain field for an anaerobic system, you can always convert it into an aerobic option. The cost of converting an anaerobic system to an aerobic one is around $7,500, on average.
Septic tanks need pumping to keep everything running smoothly. This will keep your drain field healthy in the long run. The average cost to pump a septic tank is around $410.
If the drain field isn’t that old, you may only need minor repairs to get everything back up and flowing. Drain field repairs vary drastically, as it all comes down to where the problem is located and the ease of access to repair the problem. With these considerations in mind, drain field repairs can cost anywhere from $2,000 to $15,000.
There are a few signs that indicate a failing drain field. For instance, if your septic tank starts requiring more pumping than normal, your drain field might be failing. Other signs to watch for include poor drainage after rain, standing water or sewage over the septic system, and plumbing backups in your sinks, bathtubs, and/or toilets.
All septic tanks require a leach field to properly drain and treat wastewater before it absorbs into the soil. If a home doesn't have a leach field, it's usually only because the home connects to a city's sewer line rather than a septic tank.
