How much does a leach or drain field replacement cost?
$3,000 – $15,000 full replacement cost
$1,000 – $5,000 repair or rejuvenation cost
$1,000 – $5,000 repair or rejuvenation cost
Get free estimates from septic companies near you, or view our cost guide below.
March 15, 2022Reviewed by Tom Grupa and 3 expert septic companies on HomeGuide.
Drain or leach field replacement cost
Septic drain or leach field replacement costs $3,000 to $15,000, depending on the size, slope, soil type, location, and accessibility. Leach field rejuvenation or drain field repair costs $1,000 to $5,000 on average. The cost to replace a septic tank and drain field is $4,500 to $20,000.
|National average cost||$7,900|
|Average cost range||$3,000 to $15,000|
Cost data is from research and project costs reported by HomeGuide members.
Cost to replace a leach or drain field by type
|Type||Average cost to replace|
|Anaerobic drain field||$2,000 – $6,000|
|Aerobic drain field||$7,000 – $10,000|
|Evapotranspiration drain field||$8,000 – $15,000|
|Mound drain field||$10,000 – $20,000|
- Anaerobic drain field – Anaerobic or conventional systems distribute wastewater from the septic tank into perforated pipes buried in shallow underground trenches. The pipes filter and release the treated wastewater into the soil.
- Aerobic drain field – An aerobic septic system features an oxygenated treatment tank, allowing natural bacteria to consume waste more quickly and efficiently than an anaerobic system.
- Evapotranspiration drain fields release wastewater into a watertight trench covered in sand. Wastewater evaporates through the sand directly into the air, never reaching the soil. Evapotranspiration systems are only feasible in arid regions.
- Mound drain fields are elevated above ground level and filled with sand. The constructed sand mound contains perforated leach pipes to filter and distribute wastewater pumped from the septic tank.
New leach or drain field cost factors
|Drain field replacement cost||$3,000 – $15,000|
|Move leach field||$5,500 – $21,500|
|Install new septic tank and leach field||$4,500 – $20,000|
The following factors affect the cost to install a new drain field:
- Field size – Larger homes require a larger septic tank and drain field, increasing costs.
- Perc testing costs $600 to $2,000 to determine the water absorption rate of the soil. A percolation test is required to design a septic system and drain field properly.
- Permits cost $250 to $650 and are required for all septic system or drain field installations and replacements.
- Labor typically makes up 60% or more of the cost to install a new drain field.
- Excavation costs $1 to $5 per square foot.
- Removing a tree costs $100 to $1,800, depending on the size.
- A septic tank inspection costs $150 to $450.
- Septic tank repair costs $600 to $3,000.
- Septic tank pumping costs $295 to $610 and is required when installing a new drain field.
- Sod installation costs $0.90 to $1.80 per square foot to cover the drain field after installation or repairs.
Cost to install a septic tank and leach field
The cost to install a septic tank and leach field is $4,500 to $20,000. Septic tank installation costs $1,500 to $5,000 on its own, depending on the tank size and material. Most homeowners spend $3,000 to $5,000 for a 1,250-gallon tank that supports a 3- to 4-bedroom home.
Cost to move a septic leach field
The cost to move a leach field is $5,500 to $21,500, including the new field installation and the following expenses:
- A new septic line costs $2,250 to $5,750 on average or $50 to $150 per linear foot to connect the septic tank to the new drain field.
- Excavating the old drain field costs $1 to $5 per square foot.
- Filling the old field pit with dirt and regrading the yard costs $200 to $500.
- A permit for leach field abandonment costs $100 to $250.
Regulations for abandoning a leach field vary by city, but most cities require one of two approaches:
- Leave the field lines in place, cover the area with hydrated lime and topsoil, and establish a vegetative cover above the field.
- Remove the field lines and dispose of them in a licensed landfill, fill the excavated pit, grade the surface, and establish a vegetative cover above the field.
Drain field repair cost
Drain field repair costs $1,000 to $5,000 on average for leach field rejuvenation or to replace the leach lines.
|Drain field repair cost||$1,000 – $5,000|
|Leach field rejuvenation||$1,000 – $5,000|
|Install septic aerator pump||$300 – $900|
|Replace septic leach lines||$20 – $45 per linear foot|
Replacing septic leach lines cost
Replacing septic tank field lines costs $20 to $45 per linear foot on average. Leach line replacement involves excavating and removing the old pipes, laying new perforated pipes and filter fabric, covering the pipes with plastic septic chambers, and filling the pit with dirt or sand.
Leach field rejuvenation cost
Leach field rejuvenation costs $1,000 to $5,000. Rejuvenation involves injecting air into the soil via a hollow tube, which fractures the soil and creates an oxygenated atmosphere that encourages aerobic bacteria to recolonize.
Septic aerator cost
A septic aerator pump costs $300 to $900 with installation or $200 to $600 for the unit alone. An aerator creates oxygenation within the septic tank, promoting the growth of aerobic bacteria to break down waste materials more quickly and effectively and reducing the drain field's workload.
Frequently asked questions
How does a leach field work?
A septic leach field—also called a drain field—is an underground system of perforated pipes or lines surrounded by sand, gravel, or permeable soil. Pretreated wastewater from the septic tank is distributed through the lines and then filters through the soil to remove harmful bacteria.
- The drain field is typically located in a large, flat, open area of the yard near the septic tank.
- The recommended field size depends on the home and septic tank size. Most leach fields have multiple trenches that are 18" to 36" deep, 1' to 3' wide, and 50 to 100 feet long.
- For drain fields installed on steeply sloped property, each field line's trench runs perpendicular to the slope.
How long does it take to replace a leach field?
Replacing a leach field takes 3 to 7 days on average, depending on the size, slope, soil type, and accessibility. Add two days if a new percolation test is required. The final inspection typically occurs one to two weeks after the new field is installed.
How long does a septic drain or leach field last?
A septic drain field lasts 20 to 25 years if properly built and well-maintained. Have the septic system pumped and the lines cleaned every 3 to 5 years to prolong the leach field's life.
How to tell if a drain field is failing
Look for these signs a drain field is failing:
- Slow drains or plumbing backups in sinks, tubs, and toilets
- Sewage odors from the drain field area
- Standing water in the yard over the septic tank or drain field
- Drainage problems when it rains
- Sewage puddled on the surface above the drain field
- Bright green grass growing over the septic tank or drain field
- Sunken area above the field
- Septic tank requires frequent pumping
Why do leach fields fail?
Factors that contribute to leach field failure include:
- Excessive household water usage
- Tree root intrusion
- Excessive water runoff due to storms
- Old or worn drain field lines
- Lack of regular septic maintenance and pumping
- Poor septic system design or installation
- Flushing non-biodegradable items
- Pouring grease, chemicals, or paint down the drain
- Damage or soil compaction from vehicles driven over the field
Can you have a septic tank without a leach field?
No, you cannot have a septic tank without a leach field. Building and health department codes require that septic tank systems include a drain field to treat wastewater before releasing it into the soil. Homes without a leach field typically connect to the city's sewer line instead of a septic tank.
Can a drain field be cleaned?
Drain field lines can be cleaned with a hydro-jet. Septic line hydro-jetting costs $250 to $800 on average, depending on accessibility and the severity of the blockage. Treating the septic system monthly with a bacteria packet may also help to clear clogs and improve the drain field's performance.
Can a drain field be replaced DIY?
Replacing a drain field requires permits, heavy excavation equipment, and a team of two or more workers. Local building codes may also require a new perc test. Hire a professional septic company to handle the job, as improper drain field installation can result in septic tank failure and property damage.
Finding and hiring a septic company
Before hiring a septic installer near you to fix a drain field, be sure to:
- Search for licensed septic companies with drain field repair experience.
- Choose a company that is a member of the National Onsite Wastewater Recycling Association (NOWRA).
- Get estimates from at least three companies to compare.
- Check out their reviews on HomeGuide and Google.
- Confirm the company is licensed, bonded, and insured.
- Get a detailed estimate, contract, and warranty in writing before the work begins.
- Make a payment schedule instead of paying in full up front.
Questions to ask
- Are you licensed, bonded, and insured?
- Are you a member of NOWRA?
- What experience do you have repairing septic drain fields?
- Do you charge for a repair estimate? If yes, how much?
- Should I repair or replace my drain field?
- Do you guarantee your work?
- Will the repairs require a permit? If yes, will you obtain one?
- Will the repairs affect my landscaping?
- How often should I have my septic system pumped?
- What other maintenance does the system require?
- Do you provide septic pumping and inspection services?
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