Dig (Excavate) to Locate Septic Tank or Drainfield

Installing a Domestic Septic Tank

When it comes to installing a septic tank, going down the DIY route is a popular choice due in no small part to the potential cost savings. Hiring a specialist contractor will likely cost you somewhere between £150 and £250 per day (sometimes more, depending on the location and conditions of the site), and it can take up to a week of work to install some of the larger systems. However, unless you have a mini excavator to hand, and have at least some plumbing skills and experience, we would highly recommend factoring this cost into your plans.

If incorrectly installed, an off-mains sewage system can leave you in a nasty mess; both physically and legally. Hiring a professional contractor to do the installation for you is the best way to give peace of mind that your system is suitable for your needs, reliable and legally compliant. Wrong installation is often the cause for the majority of septic tank drainage issues.

However, if you have the skills and experience to install one yourself, the following guide will take you through various steps and stages involved in planning and preparing for your installation.

Note: This guide is intended as a recommendation of points to consider when planning to install a septic tank system. It is not intended to be taken as legal advice, nor does it cover all aspects of installation for all types of septic tanks. Professional advice should always be sought to better understand the legalities of installing your system, and manufacturers recommendations and guidance should always be taken over those mentioned in this article, should they conflict in any way.

Stages of installing a septic tank

If you have already read our “How to plan and design a new septic tank system” article, you’ll no doubt have become an expert on all the legalities, requirements and rules surrounding the installation of a domestic septic tank system (if not, we highly recommend giving it a read before going any further). You will have designed your system to perfectly fit your property, while remaining fully compliant with rules and regulations, and have placed an order for the most suitable tank. Now comes the hard work…installing it all!

Once again, we do recommend that the installation of any septic tank should always be carried out by a suitably trained and qualified professional. However, if you feel you are up to the task of a DIY install, the manufacturer of your chosen tank will provide you with a detailed manual that will give step by step instructions on how to do it. This will also advise you of all the health and safety measures that should be taken throughout – please make sure you follow these in full.

As a brief guide, though, the following list of the general steps should give you an idea of what will be involved.

Creating the Drawings

Before we can start building our septic system we need to create the drawings as to meet the needs of your local health department. The actual level of detail that is required for your DIY septic system drawings may vary from state to state. However, all buildings, walkways, property lines, retaining walls and the location of the original test holes must be shown.


Extra Services

Now you should have a detailed estimate of how much you would pay for a new septic tank or whole new septic system for your home. But don’t stop there. If you want to know how much you’ll really spend on this project, there are some related services you’ll need to take into account. 

For one, you may need to prepare your property in some way before it’s ready for the installation of your septic tank. For another, you’ll definitely spend more money over the years maintaining your septic tank with regular pumping and cleaning and the occasional part replacement. 

Part replacements

If you have a problem with your septic system somewhere down the line, don’t panic. Most of the time, replacing a single part will solve your issue quickly and easily. You likely won’t have to replace the whole system or the tank itself for a few decades. 

Keep in mind, even though replacing a small part might seem easy, it’s still a good idea to hire a professional. As with installation, even a minor error can cause major problems that could be expensive to reverse. 

Tank lid$45 – $112
Baffle(s)$23 – $500
Filter$230 – $280
Riser$300 – $600
Pump$620 – $1,300
Leach field$3,375 – $12,000

Regular maintenance

Photo Credit: SuSanA Secretariat / Flickr / CC BY
Photo Credit: SuSanA Secretariat / Flickr / CC BY 2.0

For your septic system to perform to the best of its abilities for as long as possible, the tank will need regular pumping and cleaning. Experts recommend hiring a plumber (or other specialist) about every three to five years to pump your septic tank. On national average, you can expect to pay a pro $294 to $563 for pumping and cleaning. This preventative expense is much less than you would spend repairing a malfunctioning septic system. 

Percolation test cost

Before you install your septic system, you’ll need to get a percolation test from a qualified engineer to figure out the type of soil your installer will be dealing with and the height of the layers in the ground (water table, bedrock, etc). The results of the perc test will determine which type of system would be best for your property. 

Your septic tank installer might be able to conduct the perc test for you, or you may need to hire a separate professional. Either way, expect to pay between $670 and $1,430 for the test.

Land clearing cost

Photo Credit: GoingLikeSixty.com / Flickr / CC BY-
Photo Credit: GoingLikeSixty.com / Flickr / CC BY-ND 2.0

Especially on a new construction site, you may need to remove obstacles such as trees and bushes before the installers can break ground on your septic tank project. This job involves excavation and requires a lot of open space, so you may need quite a few obstructions removed. 

More often than not, you’ll need to hire a separate land clearing company to prep the area for your septic tank installation. Clearing a large space usually costs between $1,210 and $4,820.

Landscaping costs

It’s safe to assume that you won’t be happy with the appearance of your yard once your septic system is complete (unless you’re a fan of barren dirt lots). So, after installation, you may want to hire a professional landscaper to cover the site with more aesthetically appealing scenery. 

Landscaping costs are highly subjective because the umbrella term “landscaping” covers so many different services. For example, installing a new flagstone walkway will cost a lot more than planting a few bushes. In general, you can expect to spend $5 to $24 per square foot for professional landscaping, depending on the complexity of the landscape design.

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Soil Classification

The soil classification system that is being used in almost all states in the USA, is the US Department of Agriculture Soil Conservation Classification System. Most soil testing pits contain 3 or more different types of soil as you continue to look down through the soil.

FAQ About Septic Tanks

1. Can you install your own septic tank?

Short answer: No. While it is technically possible for you to install your own septic tank, the odds are very high that you’ll make a mistake that will cause you much more grief (and cost you much more money) than working with a professional in the first place.Installing a septic tank requires specialized technical knowledge you can’t gain from a DIY YouTube video. Messing up this project could cause water pollution, drive up your home insurance premiums, and make your home much harder to sell. In some places, it may even be illegal for someone without the proper license to install a septic system.

2. How do septic tanks work?

Different types of septic systems work in different specific ways, as we’ve already covered. But these are the basics. Waste from your home (anything that goes down the drain of toilets, sinks, showers, etc.) flows into the septic tank. In the tank, waste separates into three layers: the scum layer on top, liquid waste in the middle, and solid waste sinking to the bottom. Either aerobic or anaerobic bacteria break down the solid waste, which stays in the tank. Liquid waste goes through the filter before moving on to the leach field, which distributes the water into the ground in most systems. 

3. How can you tell when you need a new septic system? There are a few signs to look for that will tell you it’s time for a new septic system, or at least a repair. Signs include: — Standing water in the yard — Sewage smells — Showers, sinks, etc., in the home draining slowly  — Water and/or sewage backing up in toilets, showers, sinks, etc.

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Step 5 – Backfill the hole

Once the tank is in place, it needs to be secured in the ground with the correct backfill. Concrete, gravel or sand are the most common recommendations, but check the instruction manual to see what the manufacturer advises and follow their steps for adding backfill to the site.


  • When installing the leech field perforated pipe, make sure that you do not turn the holes in the pipe downward. The perforated drain field pipe ASTM 2729 has perforations on both sides of the pipe and must be laid dead level with the printed line on the pipe facing up. All sections of the perforated pipe are glued together and the end of each leach line is capped. This way when waste water enters the pipe, it will fill the pipe to the height of the holes and overflow from ALL of the holes using the entire leach field. Placing the perforated pipe at any slope will direct all of the water to the lowest hole in the pipe creating a concentration of sewage at only a small part of the drain field.

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  • You can in some health jurisdictions use waste water for watering grass or ornamental plants, trees, vegetable gardens and fruit trees. However, the water must be treated first by the system (tertiary treatment including disinfection) to ensure that pathogens (germs) from the septic system are not released to the environment. Check with your local health department to see if this practice known as “reuse” is allowed in your area.

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How Much Does A Septic Tank Installation Cost?

When I started looking into septic system installa

When I started looking into septic system installations, cost was my number one question, but answers were not easy to find. There is a lot of variability in the cost of a septic install, so I’ll share the price and details of my system. I also wanted to outline some of the factors that impact the price and then share examples from others I surveyed to get a complete picture.

Factors That Impact Cost Of A Septic System

There are several things that impact how much your

There are several things that impact how much your system is going to cost. It’s important to remember that while a portion of the price will be impacted by materials (largely commoditized and pretty similar costs across all your quotes), labor will be the biggest swing here. Labor costs are variable and can change based on how busy the installers are, how much of a pain they expect you or the job to be, etc. Permit costs in your area are what they are, so that will be the same across the board.

Municipality / Location – Like all things in real estate: location, location, location. The best way to understand this is to think about how your property prices compare to other areas. If you live in a high cost of living area or a town where home prices are expensive, your septic will cost more. When comparing your location to others, look at the average cost of homes, figure out the percent difference and apply that to septic costs for a rough idea.

Soil Types and Perking Tests – Soil is another major factor of cost because if you have well-draining soils, your system will have an easier time filtering the waste water. If your soil is poor, you’ll have to extend your drain lines more and more to make up the reduced capacity for the soil to filter. Basically, you make up for poor soil filtering by extending the area you filter into until it handles it properly. In some cases, soil isn’t viable or you don’t have enough room. A larger drain field equals more materials and more labor.

State Of The Economy – Simply put, when housing is booming, you’re going to pay more. If you’re in a recession, you’ll find prices to be more competitive.

How Busy They Are – The truth is installers charge more when they are busy. Much like the state of the economy, this is a supply and demand scenario. If there are enough jobs to fill their time for the next 30-90 days, they’re going to start asking for more. The trick is the good installers are often never short of work and the bad installers will pretend like they’re busy. Try to ask around and see if there is a slow season or ask the installer if there is a time that you could wait on for a reduced price. Sometimes just being flexible and willing to wait will provide an opportunity to save some money. The installer may finish another job early, the inspector may be slow on another job or there could be a cancellation.

How Much Of A Pain You’ll Be – If you seem like you’re going to be a pain to work with, the price just went up. Be friendly and punctual, but also don’t be a push over. Sketchy contractors will try to take advantage of someone’s good nature. Realize and plan for the process taking longer than you expected it to take.

Access To Site And Terrain – It’s easiest to install a system in a flat, cleared space with a wide driveway that leads right to the land. My installer wanted to visit my site to evaluate the difficulty of the terrain and ensure it was accessible. If your lot needs cleared, is difficult to access or steep, expect prices to rise pretty quickly. That said, take the time to install a good driveway and clear the spot well. It will need accomplished anyway and it can save you money in the long run.

Permit Fees And Engineering – Permit fees are what they are. In my county they charged $350 for a septic permit and there is no way around it. Some places have much higher fees. Also, you’ll pay more if your lot requires some sort of special engineering.

Pumps And Cesspools – You ideally want your septic tank to be down hill of your house and the drain lines to be down hill of your tank. In some cases, your house might not be up hill of them. If this occurs, you’ll need to install a cesspool to collect the waste that will be pumped up to the field. These two things (cesspool and pump) are additional units to your septic tank and add extra expenses. I’d suggest avoiding lots that require this because it adds cost and complexity. It’s just one more thing to break and it has moving parts which are prone to failure.

Aerobic Vs. Anaerobic Septic Systems – In some cases, a municipality will require you to have an aerobic system. The basic difference between aerobic and anaerobic septic systems is the presence of oxygen. Traditional anaerobic septic systems operated in the relative absence of oxygen; the broken-down sewage must be able to live without oxygen. Aerobic septic tanks are also located underground, they use an aerator to add oxygen into the tank. Because of the added complexity and equipment, Aerobic systems are more expensive.

Conventional Vs. Mound Septic Systems – I don’t know too much about these other than what my realtor explained to me. Basically, in certain circumstances where the soil isn’t ideal, the water table is too high or there is a lot of rock involved, a mound system is required. This system is a pile of gravel, sand and other fillers to make an elevated septic system. They typically cost more and require extra engineering costs.

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The Cost To Install My Septic

My septic was a 1000-gallon cement tank with 300 f

My septic was a 1000-gallon cement tank with 300 feet of drain line in a well-draining soil. My permit was $350 and I spent $300 for a guy to come out with a backhoe and dig pits for my perk test. I made sure to have this done before the purchase of the land, my offer was contingent upon successfully getting a well and septic permit.

I chose this place because it had minimal buildingI had the system designed for 4 bedrooms because I don’t know exactly what I want to do. Most likely I’m going to have a Master bedroom and a guest bedroom, then space to put two more bedrooms in the future (I’d finish them if I sell to increase resale value). My land is located in the mountains of NC which is pretty rural and low cost of living.

I chose this place because it had minimal building codes, no HOA or restrictions, and the county was pretty inexpensive tax wise. I say this for you to know that my scenario was the cheaper end of the spectrum. The one thing working against me was I had no contacts in the area at all, so I did my best to get multiple quotes. In the end I think I ended up spending more than I had to, but I got very close to what others were paying at the time. I was on a time crunch as my permit expired at the end of the year, so I couldn’t delay things. After three quotes I settled on a contractor that I liked for $7,500 all in.

Cost To Install Other Systems

I took some time to get a better picture of costs

I took some time to get a better picture of costs by talking with several other people. Here is a breakdown of what their systems cost when they installed their septic system.

Louisiana $7,000 1,000 Gallon Tank 5 Bedrooms 400 Feet Installed in 2015 California $30,000 1,800-Gallon Tank 4 Bedrooms 350 Feet Installed in 2020 Tennessee $3,500 1,000-Gallon Tank 3 Bedrooms 230 Feet Installed in 2012 Ohio $7,000 2,000 Gallon Tank 4 Bedrooms 500 Feet Installed in 2004 Texas $5,000 1,000-Gallon Tank 4 Bedrooms 300 Feet Installed in 2013 Oklahoma $3,600 1,000-Gallon Tank 3 Bedrooms 400 Feet Installed in 2007 Nevada $7,500 1,250 Gallon Tank 3 Bedrooms 500 Feet Installed in 2005 California $8,500 1,500-Gallon Tank 3 Bedrooms 275 Feet Installed in 2019 Washington $5,000 1,000-Gallon Tank 2 Bedrooms 300 Feet Installed in 2018 Michigan $8,000 1,500 Gallon Tank 4 Bedrooms 3 900-Gallon Dry Wells Installed in 2019 Your State Your Cost How Many Gallons? How Many Bedrooms? How Many Feet of Drain Line? When Was It Installed?

Let us know in the comments if you’ve had a septic installed and the details.

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Whether planning a new installation or replacing your current tank, it’s crucial to select a system that will work with your household size, climate, and local environment. Although DIY septic tank installations are possible, we do not recommend them unless you have professional experience. Instead, you should consult a professional installer to complete your job. Research at least three installers in your area and compare the quotes, available equipment, labor costs, and warranty options.

Use the tool below to find local plumbers in your area to help with your septic tank installation.