Septic System Installation Costs: Materials and Labor

Navigating the financial considerations of septic system installation demands a clear understanding of the associated labor and materials costs. In Ace’s septic system installation cost guide, we aim to provide a breakdown of expenses, focusing on the professional labor and essential materials required for a successful septic system. By reviewing each cost component, you will gain valuable insights into the financial aspect of this crucial infrastructure investment, enabling informed decision-making and efficient project management.

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This guide focuses on the costs associated with each step of your septic system installation. There are five steps to complete an install. More on the details of those five steps and why use a licensed septic contractor here.

The costs below are based on a 3 bed 2 bath single family dwelling installation in Colorado. These estimates are based on both conventional systems and engineered systems.

1. System Design ($2,000 – $3,000)

There are several different costs in a septic system design. First, you have excavation costs associated with digging pits for the engineer’s soil test. Expect to spend $500 on these perc/soil test excavation costs, and another $1,500 – $2,500 for the engineer fees and permit. To get a permit for septic installation in Colorado you must use a Colorado engineer’s stamped design, per the Department of Health.

For more on Colorado’s OWTS regulations visit the Regulation 43 guides from the Colorado Department of Health. Here is an example of the soil test pits the engineer needs to determine your soil profile:

septic system installation costs soil test pits

2. Tank and Leach/Drain Field Excavation ($2,500 $10,000)

Excavation costs vary greatly in Colorado due to the varying soil conditions. This is why the estimated cost has such a large range. If your land is full of vehicle sized granite boulders, expect to be on the higher end. Those in the eastern planes benefit from softer soil conditions and less rock, and can expect excavation costs to be less.

This is debatably the most important step of your septic system installation. The grade must be perfect for gravity fed systems to work properly. Colorado is also known for its swelling soils, which makes excavation even more crucial. If you want to save money and DIY your septic system installation, excavation is not the area to do it. (Unless you have experience in this field already.)

3. Materials and Labor: Tank, Pump and Leach Field ($7,000 – $23,000)

Conventional septic systems are cost-effective, relying on basic design principles for wastewater treatment. The drawback to a conventional system is they are not available for everyone. Those basic designs are not effective in specific soil types. Soil type is determined during system design, and your installer will work with the engineer to source equivalent parts when needed. In other words, you don’t have to worry about supply issues wreaking havoc on your septic installation.

Engineered systems involve advanced technologies tailored to unique site challenges, complying with regulations. Consequently, the latter incurs higher costs for specialized components, design considerations, and professional expertise. Not to mention those complicated systems require more time and labor to install.

4. Septic System Inspection (FREE – $1,000)

Inspection fees only accumulate if you fail your initial inspection, most of the time. Depending on your location, and the agreement with your engineer, these fees can add up to hundreds of dollars with each visit. No matter how qualified your installer is, inspections can fail due to numerous reasons. For example, a manufacturer defect in pump seal can cause a failed inspection. Without parts on hand a new inspection is required after warranty/replacement of the defective parts..

The good news is, qualified installers know how to properly test the system before county inspectors and engineers get on site. When installed and tested properly, final inspections are seamless 95% of the time. This is why it is paramount to work with a licensed septic system installer, like Ace’s Garden.

5. Backfill and Site Cleanup ($500 – $2,000)

Most contractors will have a minimum of $500 in labor, fuel and other overhead costs to push the recently excavated dirt back into a hole. Some areas may require ground cover like straw blankets or sod. A licensed septic contractor, like Ace’s Garden, takes care of getting those answers for you.

The cost of ‘finishing’ is as variable as your desire to make the space look good. Keep in mind, your leach/drain field will be an area you cannot put anything on top of. Doing so can create compaction and cause the system to fail, requiring removal and new installation costs.

Total Septic Installation Costs in Colorado: $12,000 – $39,000

The biggest variable of your septic system installation cost is materials. Materials are determined by system type, which comes from the engineer. (It seems complicated, but an engineer designs both conventional systems and engineered systems. Engineered systems install in soil profiles that drain poorly. Coincidently, that soil is also difficult to excavate. Meanwhile, for a conventional system you have much better soil for drainage, which also means easier excavation in most cases.

When speaking with contractors regarding your septic system installation, be sure to clarify whether you are getting an estimate or a bid. There is a big difference between the two, and one could do serious damage to your pocketbook. Ace’s Garden provides a bid on all of our septic jobs. That means there are no surprises on your final invoice for septic system installation costs.

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