How Much Does a Septic Distribution Box Replacement Cost? [2025 Data]
The average septic distribution box replacement costs $1,000, but it can range between $500 and $1,500, depending on the labor involved, house size, and materials involved.
A septic distribution box (or D-box) is connected to the septic tank and spreads wastewater throughout the leach field underground. Here’s why a D-box is so important for your home—it prevents flooding and keeps the ground from collapsing from large amounts of water. While most D-boxes last a long time, they can sometimes need replacing if they break or crack with age, after a tree root grows too close, or after heavy flooding. It typically costs about $1,000 to replace one, though the cost can range from $500 to $1,500.
In this cost guide, we outline what you’ll need to budget for your septic distribution box replacement costs.
What Factors Influence the Cost to Replace a Septic Distribution Box?
The cost of the septic D-box itself doesn’t fluctuate very much, but the two factors that do change the price include the size of the D-box and whether it’s made of concrete, plastic, or fiberglass. As you plan out your project, consider these factors:
I had another company design my septic system replacement, but Paul re-designed it to avoid having to remove a 50+ ft tall tree and added a drainage system for the water from the gutters. The old no-longer-up-to-code 2-cesspool septic system was replaced by a drainfield and Ecoflow septic tank. The work was done on the days I was told workers would be here (unlike the company that drew up the first set of specs), and Paul and Jon were always friendly and great to work with.
Size
| Box Size | Average Cost |
|---|---|
| 3-outlet | $60–$80 |
| 4-outlet | $70–$110 |
| 5-outlet | $90–$150 |
| 6-outlet | $110–$180 |
| 7-outlet | $130–$220 |
| 8-outlet | $140–$250 |
The size of your household will determine your septic needs, so the larger your home, the larger your septic tank will need to be to avoid filling up too fast. That means the septic distribution box will also need to be larger to accommodate spreading the volume of wastewater into the leach field.
The larger the box, the more it will cost, but you’ll likely save more in the long run by not having to get the septic tank pumped as often. Pumping a septic tank costs $400, or $0.30 per gallon on average.
Distribution box sizes are not categorized by their volume as you might expect, but by the number of outlets they have. These outlets hook up to the septic lines that drain into the leach field. The larger the house, the more septic lines are required. The good news is that larger boxes aren’t much more expensive than smaller ones.
Material
Septic distribution boxes are typically made of concrete, plastic, or fiberglass.
| D-Box | Average Cost |
|---|---|
| Plastic | $70–$200 |
| Concrete | $90–$400 |
| Fiberglass | $50–$200 |
Plastic is the least expensive, while concrete costs the most. However, they each have their pros and cons. For example, concrete lasts for decades but can be prone to corrosion. Plastic and fiberglass are lighter and easier to install, but may not last as long as concrete and have the potential to float when groundwater is high unless properly anchored.
Installation Labor
A septic tank repair person typically charges around $160 per hour of work, though some companies charge 50% to 70% of the total project cost versus a per-hour rate. You can research local septic tank repair companies with good reviews in your area and collect a few quotes to compare pricing.
Grading and Landscaping
If you need a D-box replaced, it means one is already installed, so chances are you won’t need any grading or landscaping done. However, ground shifts over time, and your septic system may need to shift with it. Large tree roots pushing against the box or septic lines are another potential reason to grade or landscape a new D-box location. Expect to pay hourly rates between $80 and $190 due to heavy machinery being involved.
Permits
Some states like Oregon and Florida require residents to apply for a septic system repair permit before having any work done. In Florida, the fee is $300 to repair an existing system, but the total cost can vary based on the specific city and state you live in. Check in with your local municipal office to see what it costs in your area.
Replacing a Septic Distribution Box Yourself vs. Hiring a Pro
This is a job best left to the professionals. While you technically could replace the D-box yourself, there’s a lot of physical labor involved digging up the box, properly disconnecting it from the rest of the septic tank system, and correctly installing the new one. A lot could go wrong and you don’t want to have plumbing issues in the future because of it.
Local septic tank repair professionals have all the specific equipment needed to get the job done correctly and in a timely manner so your household can go back to using the toilet, shower, and sinks as normal without any damage to your home.
Frequently Asked Questions
Septic distribution boxes, also called D-boxes, tend to last over 30 years if taken care of extremely well. In most cases, however, they tend to last anywhere from 15 years to 40 years. Regular cleaning and maintenance, as well as living in an area that doesn’t flood the tank or the system regularly, will all have an impact on the lifespan of the box.
A septic tank should be pumped once every three to five years or sooner if there’s a problem with your plumbing backing up. A large 5+ person family who frequently has guests over using the bathroom or who pours a lot of water and food down the garbage disposal may need to get it pumped closer to every two years.
A septic system inspection costs $100 to $200. Doing so can spot issues early so you can plan for necessary repairs ahead of time and save yourself the issue of a backed-up septic tank. Some septic tank repair professionals do an inspection as part of their yearly maintenance on your septic tank if you choose to pay for that service, but you should shoot to have a septic system inspection completed at least once every two to five years.
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