Get matched with top septic tank pros in Boulder, MT

Q: How much does it cost to replace or install a new septic tank?

• <div><p>The average cost to replace a septic tank or install a new system is typically around $7,350, with a broader average range of $5,000 to $12,000. However, total project costs can vary widely, from $5,000 to as much as $22,500. Key factors influencing the price include the size and type of the septic system, the tank material, and the size of your house.</p><p>It's important to distinguish between the cost of the tank itself and the cost of the entire system installation, which is significantly more. For the tank alone, costs vary by size:</p><ul><li><p>A tank for a one-bedroom house typically costs $500 to $900.</p></li><li><p>A 1,000-gallon tank, suitable for most one- to three-bedroom homes, costs between $900 and $1,500.</p></li><li><p>A tank for a five- or six-bedroom home generally costs $1,200 to $1,600.</p></li></ul></div>

Q: How deep is a 1,000-gallon septic tank?

• <div><p>The depth of your septic tank has nothing to do with its size. In fact, some septic tanks can even be installed above-ground! Like other sizes, a 1,000-gallon septic tank could be buried as shallow as 4 inches below the ground or as deep as 4 feet. It all depends on your specific property.</p></div>

Q: How deep are septic lines buried?

• <div><p>Septic drain lines (or leach lines) are typically buried between 18 and 36 inches underground, and should be at least 6 inches below the surface. These pipes are perforated and surrounded by filtering materials like sand or gravel. Burying the lines at this depth helps minimize odors and allows bacteria and other biological processes in the soil to effectively treat the wastewater. Burying lines too close to the surface can cause issues unless the soil is very compact and stable.</p></div>

Q: What does a full septic tank look like?

• <div><p>A septic tank always has some amount of liquid in it&mdash;which should usually be 8 to 12 inches from the top of the tank. If the liquid level is higher than that or is overflowing the drainage pipe that leads out to the leach field, the tank may be too full and in need of pumping.</p></div>

Q: How often should a well pump be serviced?

• <div><p>Ideally, you should conduct a mechanical inspection and a bacterial or <a href="https://www.angi.com/articles/well-inspection-checklist.htm">well water inspection</a> yearly. While you might be able to push it off to every other year, it&rsquo;s best to have peace of mind, especially when it comes to something that you use so frequently. </p><p>If you experience repeated gastrointestinal illness in the household, it's important to test the well water more regularly for quality and cleanliness to check for bacteria.</p></div>

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Verified Reviews for Septic Tank Service pros in Boulder, MT

*The Angi rating for Septic Tank Service companies in Boulder, MT is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Septic Tank Service needs.

*The HomeAdvisor rating for Septic Tank Service companies in Boulder, MT is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Septic Tank Service needs.

Last update on March 20, 2026

Reviewed in March 2026
Very polite. Completed the job quickly, did a quality job and cleaned up before leaving.
Smith Construction, Inc.
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Reviewed in November 2024
Everything went very smooth with the first consult all the way through to the texts leading up to the install. Great group of people to work with!
Renewal by Andersen of Montana
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Reviewed in August 2024
Great people to work with, family business, trustworthy, did an excellent job ripping up and replacing our driveway. They completed the job in one day and without any issues. Attention to detail. Highly recommend them and you won't have to worry about the quality of the job they'll do.
Ted's Asphalt Repair
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Reviewed in March 2024
Professional, right on time, quickly completed as scheduled. We will use them again.
Madison River Excavation
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Reviewed in November 2022
Nathan is an excellent worker who works speedily and professionally. He replaced our dining room and bathroom floor and did such an excellent job that we want to hire him back to do our kitchen floor!! I would recommend Nathan to anyone!!!
Freedom Flooring
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Reviewed in October 2021
Royal Construction managed a 6000 sgft Unique Log Home construction and finishing, inside & out, over multiple phases. Shane & his crew were detail oriented, overly efficient in design and material usage, punctual and 100% reliable to his word and bids. We would not have been able to...
Royal Construction & Remodeling
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Reviewed in December 2020
We went into the Helena location in July and picked out a shed to be built. We were told 8-10 weeks from time of order, so we put $1800.00 down that day. We were told we would receive updates along the build, and to expect our shed in late August, early Sept. By mid Sept, we still had no shed,...
TUFF SHED INC - Helena
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Reviewed in June 2020
John was extremely friendly, suggesting others to do portions of the work where he didn't consider himself an expert. They were, and the job was done right. For the part he did, the work was fast, clean, and done with a smile. He's my new go-to plumber in the Boulder/Helena area.
Sorensen Plumbing
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Reviewed in April 2020
He is very meticulous, takes pride in his, work, and makes sure whatever he does is done to code. I was pleased with the work he did for me!
DLH Electric
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Reviewed in October 2016
The folks at Finstad's did a wonderful job with our flooring. It started with Chris coming out to give us ideas and options to Todd doing an exceptional job of installing the flooring from carpet to laminate. Chris and Todd made this an easy and enjoyable process and there is never a doubt...
FINSTAD'S CARPET ONE
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Find Septic tank pros in Boulder

K & E Enterprises, Inc.

5.0(

)

Serving Boulder, MT and surrounding areas

In business since 2007

Free estimates

Response time2 days

Recommended by100%of homeowners

Serving Boulder, MT and surrounding areas

In business since 2008

Emergency services offered

Credit card accepted

"Well. Only problem was delay in response time after claim was filed online. Water tank started leaking Thanksgiving morning and no reply until I called the Regional Manager."

Recommended by82%of homeowners

Serving Boulder, MT and surrounding areas

In business since 2017

Free estimates

Emergency services offered

We take great pride our experience, expertise, quality, and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

Response time3 hrs

Recommended by100%of homeowners

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American Home Shield – Home Warranty

3.5(

5,688

)

Serving Boulder, MT and surrounding areas

In business since 1971

Credit card accepted

"I just pay $75 you never know who's going to come out. They do everything electrical. Just about everything is covered except the septic tank. I had an air conditioner replaced. It went great, all I had to do was pay for the freon. He didn't charge e more than what was needed."

Recommended by65%of homeowners

Serving Boulder, MT and surrounding areas

In business since 2019

Free estimates

Offers commercial services

We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business!

Response time40 mins

Recommended by66%of homeowners

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KMD Construction LLC

New to Angi

Serving Boulder, MT and surrounding areas

Free estimates

Emergency services offered

Small jobs welcome

We are an excavation/concrete company we do septic tanks, sidewalks, driveways, landscaping, demolition, and fencing. We are here for all your needs. Give us a call at 406-465-7954 for a free quote

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Thin Air Excavation

New to Angi

Serving Boulder, MT and surrounding areas

In business since 2022

Free estimates

Credit card accepted

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Freedom Fabrication and Metal Art, LLC

5.0(

)

Serving Boulder, MT and surrounding areas

In business since 2012

Free estimates

Credit card accepted

Response time2 days

Recommended by100%of homeowners

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Devers Excavation Contracting

New to Angi

Serving Boulder, MT and surrounding areas

In business since 2024

Free estimates

Offers commercial services

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Rocky Mountain Excavation & Grading, LLC

New to Angi

Serving Boulder, MT and surrounding areas

In business since 2018

Free estimates

Emergency services offered

Rocky Mountain Excavation & Grading, LLC is committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers interests and make their concerns the basis of our business.\n

Response time12 hrs

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Showing 1-10 of 11

Septic Tanks questions, answered by experts

The average cost to replace a septic tank or install a new system is typically around $7,350, with a broader average range of $5,000 to $12,000. However, total project costs can vary widely, from $5,000 to as much as $22,500. Key factors influencing the price include the size and type of the septic system, the tank material, and the size of your house.

It's important to distinguish between the cost of the tank itself and the cost of the entire system installation, which is significantly more. For the tank alone, costs vary by size:

A tank for a one-bedroom house typically costs $500 to $900.
A 1,000-gallon tank, suitable for most one- to three-bedroom homes, costs between $900 and $1,500.
A tank for a five- or six-bedroom home generally costs $1,200 to $1,600.

The depth of your septic tank has nothing to do with its size. In fact, some septic tanks can even be installed above-ground! Like other sizes, a 1,000-gallon septic tank could be buried as shallow as 4 inches below the ground or as deep as 4 feet. It all depends on your specific property.

Septic drain lines (or leach lines) are typically buried between 18 and 36 inches underground, and should be at least 6 inches below the surface. These pipes are perforated and surrounded by filtering materials like sand or gravel. Burying the lines at this depth helps minimize odors and allows bacteria and other biological processes in the soil to effectively treat the wastewater. Burying lines too close to the surface can cause issues unless the soil is very compact and stable.

A septic tank always has some amount of liquid in it—which should usually be 8 to 12 inches from the top of the tank. If the liquid level is higher than that or is overflowing the drainage pipe that leads out to the leach field, the tank may be too full and in need of pumping.

Ideally, you should conduct a mechanical inspection and a bacterial or well water inspection yearly. While you might be able to push it off to every other year, it’s best to have peace of mind, especially when it comes to something that you use so frequently.

If you experience repeated gastrointestinal illness in the household, it's important to test the well water more regularly for quality and cleanliness to check for bacteria.

The Boulder, MT homeowners’ guide to septic tank services

From average costs to expert advice, get all the answers you need to get your job done.

See all articles

Taylor Freitas
•
Mar 18, 2026Mar 18, 2026
How Much Does Septic Tank Repair Cost? [2026 Data]
A damaged septic system can leak odors and sewage, so repairs are urgent. Find out how much septic tank repair costs based on repair type, tank size, and more.
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•
Mar 18, 2026Mar 18, 2026
How Much Does It Cost to Locate a Septic Tank? [2026 Data]
If it’s been there for a while, it can be hard to find the septic tank in your yard. Learn how much it costs to locate a septic tank with this guide.
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•
May 22, 2026May 22, 2026
Crank Up Your Understanding of Septic Tank Volume
It’s crucial to install a septic tank with the right volume to avoid wastewater backups. This guide will help you calculate the right septic tank volume.
Jamie Cattanach
•
May 22, 2026May 22, 2026
What’s the Right Septic Tank Size for Me?
Septic tank sizes vary depending on the size of your home, how many people live there, how much water you use, and more. Read on to learn how to determine the right size for you.
Taylor Freitas
•
May 21, 2026May 21, 2026
Are Septic Tanks Bad? Pros and Cons to Consider Before Moving Into a House With a Septic System
If you’ve never lived in a house with a septic system before, you might be wondering: Are septic tanks bad? Here are some of the pros and cons.
Taylor Freitas
•
Apr 8, 2026Apr 8, 2026
How to Build a Small Septic Tank for a Rural Property
Want to learn how to build a septic tank for your rural or off-grid property? First, check your local laws, then dive into these general guidelines.