How Much Do Mound and Conventional Septic Systems Cost?

Last Updated on October 2, 2024
Written by CPA Alec Pow | Content Reviewed by CFA Alexander Popinker

For homes not connected to a municipal sewer system, installing an on-site septic system is vital for the safe treatment and disposal of household wastewater. The two most common options are mound and conventional septic systems. But how much does each type cost on average?

This guide covers everything potential buyers need to know about the pricing, costs, and value considerations when choosing between septic system types.

How Much Do Mound and Conventional Septic Systems Cost?

Mound septic systems typically cost from $15,000 to $30,000 professionally installed while conventional septic systems usually cost $5,000 to $10,000 depending on size and features.

The pricing variance stems from differences in materials, excavation, specialized equipment like dosing pumps, and overall construction complexity. Ongoing maintenance expenses also warrant consideration when evaluating the total long-term costs over the lifespan of each system.

Due to their unique multi-layered construction and specialized equipment like dosing pumps, mound septic systems are typically more expensive for both materials and professional installation labor. Here are the average mound septic system costs according to users:

All-In Mound Septic System Installation Costs

On average for a professionally engineered and installed complete mound septic system:

• Small capacity mounds for 1-3 bedrooms: $15,000 to $20,000
• Large capacity mounds for 4-6 bedrooms: $20,000 to $30,000

Many factors like slope grade, native soil depth, consistency and absorption rate, and local labor costs can influence final pricing significantly. Poor site characteristics increase costs.

Breakdown of Mound Septic System Material Expenses

The major categories of construction materials involved for a mound septic system include:

• Baffled septic tank – $2,000 to $6,000
• Mound sand fill – $3,000 to $8,000 per mound
• Gravel bed – $1,000 to $3,000
• Distribution piping – $1,000 to $2,000
• Dosing pump system – $1,500 to $2,500
• Retaining walls – $2,000 to $6,000
• Topsoil and landscaping – $1,000 to $3,000

The volume of imported sand and gravel make up a large portion of the material costs. The septic tank itself along with the dosing pump are also pricey line items.

Typical Maintenance Costs

To keep mound systems operating properly, owners should budget the following routine maintenance expenses over time:

• Professional pumping – $350 every 3-5 years
• Annual inspections – $150 to $300
• Routine landscaping care – $250 per year
• Sand mound renewal – $2,000 every 10-15 years

Proactive maintenance helps prevent expensive failures or backups. But do expect recurring costs.

Potential Repair Expenses

If substantial issues arise requiring corrective repairs to restore proper functioning, costs for mound septic systems can range $4,000 to $15,000+ to rebuild sand mounds, replace drain piping, repair retaining walls, or swap out failed components like pumps or control panels. Attempting DIY repairs risks further damage and is not advised.

According to Angi, the average cost for a septic system installation ranges from $3,546 to $11,854, with an overall average around $7,696. Mound systems, which are often used in areas with poor drainage, can typically cost between $10,000 and $20,000.

Another source, Today’s Homeowner, notes that conventional septic systems generally cost between $3,500 and $11,000. They emphasize that while the cost of the tank itself may be relatively low (ranging from $500 to $2,500), labor and installation fees can significantly increase the total price.

A detailed overview on NexGen Septics indicates that conventional systems are among the most common and affordable options, costing around $2,000 to install. In contrast, mound systems are more complex and can lead to higher installation costs due to additional materials and labor required.

According to another article on U.S. News, the national average for septic tank installation is about $6,000. This figure includes various types of systems but highlights that mound systems may incur additional costs due to their specific requirements.

Mound and Conventional Septic Systems

To understand cost differences, let’s first briefly cover what each system entails:

Mound Septic Systems

A mound system consists of an elevated sand bed and gravel trench where wastewater is distributed for treatment by bacteria. The mound allows proper drainage and filtration when native soil has low absorption. A dosing pump feeds the mound. These are common for areas with high groundwater.

Conventional Septic Systems

Traditional septic systems rely on a below-ground septic tank and soil absorption drain field. Wastewater separates in the tank, then flows to the stone and gravel trench. Natural bacteria treat waste as it filters through the soil. This is the most widespread residential system.

Mound systems require imported soil, complex pumping, and excavation, making installation more expensive. But in the right conditions, maintenance costs are comparable for both options.

You might also like our articles about the cost to pump out a septic tank, to connect to a public sewer, or to install an aerobic or anaerobic septic system.

Factors Influencing the Pricing

Several considerations affect the installation and long-term expense:

Degree of Soil Absorption – Soil testing determines the rate at which effluent can permeate into the ground, measured in minutes per inch. Faster absorption lowers costs. Slow absorption requires sand mounds or special systems.

Size, Footprint, and Capacity – Larger homes with more fixtures and occupants require bigger systems and tanks, increasing costs. The mound or drain field size also grows.

Complexity of Installation – Mound systems require extensive excavation, materials transport, pumping systems, retaining walls, and landscaping. Conventional systems need simpler trenches. More labor means higher costs.

Permitting and Compliance Requirements – Septic permits and required inspections vary by county. Complex requirements or strict environmental regulations also increase mound system expenses.

System Materials – Mounds require sand, gravel, dosing tanks, retaining wall materials, reinforced piping, and other hardware while conventional systems need less equipment. Expenses add up.

Typical Conventional Septic System Costs – Thanks to their comparatively straightforward excavation and installation, conventional septic tanks and leach field systems carry lower upfront costs but require ongoing periodic pumping and maintenance. Here are the typical price ranges:

Conventional Septic System Installation Expenses

For a professionally engineered and installed complete conventional septic tank and drain field system for a single family residential property:

• Small capacity for 1-3 bedrooms – $5,000 to $8,000
• Large capacity for 4-6 bedrooms – $8,000 to $12,000

Regional location, tank size, native soil characteristics, permitting complexity, and total drain field trench length all impact final costs.

Conventional Septic System Material Costs

The primary materials expenses for a conventional septic installation include:

• Septic tank (concrete or polyethylene) – $2,000 to $6,000
• Drain field piping – $1,000 to $3,000
• Gravel or crushed stone – $500 to $2,000
• Inspection pipes – $500 to $1,000

Tank selection and size represents the biggest equipment cost. Opt for corrosion-resistant, durable tanks.

Operation and Maintenance Costs

To keep conventional septic systems working properly, budget for:

• Professional pumping – $300 every 3-5 years
• Annual inspections – $100 to $250
• Field upkeep – $100 per year

Routine pumping prevents sludge accumulation and early component failures. Annual inspections identify any issues arising.

Potential Repair Expenses

If extensive repairs are needed, costs for conventional septic systems may run $2,000 to $8,000+. Fixing clogged piping or replacing drain field sections demands excavation. Tank repairs or replacement range $2000 to $4000. Compare quotes before approving repairs.

Mound vs Conventional Septic System Costs

Now that we’ve examined costs for each system independently, here is a summary comparison:

Cost Factor	Mound Septic System	Conventional Leach Field System
Average Installation Range	$15,000 to $30,000	$5,000 to $10,000
Typical Material Expenses	$10,000 to $20,000	$4,000 to $10,000
Average Annual Maintenance	$700 to $1000	$400 to $600
Potential Repair Expenses	$4000 to $15,000+	$2000 to $8000+

Over a 20–30-year lifespan, long-term care costs ultimately even out between the two septic configurations. However, mound septic systems often carry double or triple the upfront installation investment as conventional systems.

Regional Cost Variations

Where you live significantly impacts septic system costs:

• Rural areas average 10-30% below costs listed based on lower labor rates and permit costs.
• Major metro areas range 20-50% above national averages based on higher wages, real estate, and strict regulations.
• Environmentally sensitive regions like lakesides or coastal areas often have intensive install and compliance rules that raise costs.

Always obtain local area quotes rather than assuming national pricing. Regional differences are very real.

Financing Options

Due to potentially high upfront costs, financing assistance can help buyers:

• Home improvement loans and mortgages allow borrowing at competitive rates to cover septic system installation without large cash outlay. Loans amortize costs over years.
• Government assistance programs like USDA Rural Development offer grants or low-interest loans to qualifying applicants in eligible areas.
• Contractor financing programs are offered by some septic companies to make costs more affordable through low monthly payments at 0% interest over 6, 12 or 24 months. Promotional financing deals are sometimes offered.

Saving up over years or pursuing financing ensures homeowners don’t delay necessary septic upgrades when needed. Financing makes projects cash-flow manageable.

Reducing Expenses

Here are great ways to control costs:

• Obtain quotes from several reputable contractors to find the best rate on labor and materials.
• Practice regular maintenance like inspections and pumping to prevent expensive failures or backups.
• Research affordable alternative materials that meet code without compromising quality. For example, polyethylene vs concrete septic tanks.
• Only install system capacity you need based on home size and occupancy to avoid overbuilding.
• If adding onto your home, carefully plan expansion to leverage previous septic investment where possible.

Final Words

When weighing mound vs conventional septic systems, upfront cost is just one factor. Soil conditions, capacity needs, regulations, and maintenance matter too. While mound systems often carry higher initial costs, they provide effective treatment in challenging areas.

Weigh all considerations against your specific property constraints and septic needs. With proper research and regular upkeep, septic systems provide essential, affordable household wastewater treatment for decades.

Answers to Common Questions

Do mound septic systems need to be pumped?

Yes, mound septic systems require periodic pumping just like conventional septic tanks, generally every 3-5 years. Routine pumping prevents sludge buildup, extends the drain field lifespan, and prevents expensive clogs or backups.

How long will a mound septic system last?

With proper installation and consistent maintenance like pumping every 3-5 years, a mound septic system can provide effective wastewater treatment for 20-30 years. Harsher climates or poor maintenance shortens mound lifespan. The pump may need replacement every 10-15 years.

How much room do you need for a mound septic system?

A mound septic system requires space roughly twice the size of the home’s foundation. A 1500 square foot home needs a mound approximately 50-60 feet long by 35 feet wide. Sufficient area is crucial for proper operation and allows future repairs if ever needed.