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Can You Pour Concrete Over Septic Lines?

You might be considering pouring concrete and building something over your septic lines to utilize most of your space. However, you're wondering whether it is okay or not. You're a moment away from knowing our findings below!

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You can certainly pour concrete over your septic lines to secure them from naturally damaging factors. Just ensure not to "float" or make the septic lines flowing path go in reverse.

However, if you opt to build something on top of your septic lines, refer first to your local building code. As septic systems have specific building codes that require you to comply with.

Either remodeling or building a new septic system, the process requires a complex task and construction knowledge. Besides, all of the standard building requirements that are mandated by your local code must be implemented. Please continue reading to learn the other important information below!

Man pumping out house septic tank, Can You Pour Concrete Over Septic Lines?

Important Septic System Guidelines

Before you proceed to construct, replace, or even alter your septic system, you must first get a Septic System Construction Permit or SSCP from your local authorities. This is especially necessary for septic disposal treatment.

Cesspool on the backyard green lawn

What Is The Average Capacity Of A Septic Tank?

The precise measurement of septic tank capacity is determined by the number of dwelling units. For instance, a septic tank connecting one to five dwelling rooms can hold wastewater of around 750 to 1,500 gallons.

Additionally, septic tanks must have at least two chamber rooms inside to effectively detain the wastewater.

What Is The Average Size Of A Septic Tank?

The 1,500 septic tank capacity has an average length of 10 feet and 9 inches. Its width dimensions are 5 feet and 5 inches by 6 foot depth. This septic tank size is sufficient for five dwelling rooms.

How Thick Are Septic Tank Walls?

Depending on where state you reside in the U.S, but in case you live in California, you shall refer to your local building code for specific requirements and further details of constructing a septic system.

According to their code, if you opt for a concrete septic system, the septic tank top face shall have a minimum thickness of four inches. Plus, all sides of walls along the bottom floor shall have a six inches thickness.

For Brick, Concrete Block, And Tile Septic Tank Applications

You shall compose the pouring concrete with one part cement and two parts of sand and four parts aggregate.

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Septic Tank Plastering Compound And Right Mixing Ratio

Following the brick, tile, and concrete block type of septic tank. You shall use only a Portland cement mortar with a mixing ratio of one part Portland cement and three parts of pure sand.

What Pipe Is Best For Septic Lines Use?

Ideally, you can use an Acrylonitrile Butadiene Styrene (ABS) or Polyvinyl Chloride (PVC) type of pipe. A schedule 40 PVC of four inches diameter is best for connecting your home wastewater to the septic tank drainage.

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What Steel Bar Size Is Great For Septic Tank?

Septic tanks are always susceptible to the earth's constant movement and extreme water pressure. All sides of septic tank walls and both ground and top surfaces shall have a supporting rebar with 8 mm size.

Is It Okay To Pave Your Septic Drainfield?

The drainfield of your septic system is where all the wastewater goes through after discharging from the septic tank. It should be situated five feet away from any buildings.

The idea of paving your septic drainfield will only lead to its surface becoming a parking space. You must not pave the drainfield to avoid unnecessary misconceptions about someone who mistakenly parks above it.

New construction of a packed bed septic leaching field in a rural residential house for wastewater treatment

Besides, if the drainfield obtains pressure by driving over it, it exposes the soil above it to excessive compaction.

As a result, it affects the drainfield evaporation process due to the lack of breathing room caused by compacted soil.

Can I Build A Structure Over The Septic Tank?

The common mistake among many homeowners is they tend to build a structure over their septic tank. As you often see some septic tanks are located under different structures or additional setups, such as:

  • Patio.
  • Driveways.
  • Vegetation.
  • Wooden deck.
  • Permanent playground.
  • And other structures.

It doesn't mean you notice a septic tank under a variety of structure setups, you will also follow it. Unless your septic tank has specific provisions as per its overall structural safety, otherwise, constructing over it is strictly forbidden.

In essence, it is not advisable to build any structures on top of the septic tank. As it makes septic system maintenance challenging to fulfill. Driveways are notably bad on top of the septic tank.

Even only driving the septic lines will result in significant piping or drainfield lines damage. So take the extra careful building over the septic tank to prevent irreversible damage.

What Can You Build On Top Of A Septic Tank?

There are always considerations and limitations to building over the septic tank. This is to ensure that your septic system is free from any harmful effects around it.

You can build a protective fence over the septic tank. But you must carefully erect its post far enough to the septic's wall. Since you have already set in place your fence.

You can utilize the septic unused space to give your lovely pets free time to play. Don't worry! It is practically safe given that these are all lightweight. This will not pose intense stress to your septic's surface flooring.

What Plants Are Safe And Trees To Avoid For Landscaping The Septic Tank?

Undoubtedly, homeowners like to add a screening to their septic tanks to make them more appealing. In addition to constructing a building over it, landscaping the septic tank with damaging plants and trees are surely not a good idea.

Lawn septic tank with concrete manhole cover

Here are the acceptable plants you can choose to enhance the aesthetic of your septic tank:

  • Pennisetum.
  • Deschampsia.
  • Feather grass.
  • Monkey grass.
  • Tufted fescues.

Avoid Plants And Trees With Invasive Roots

Planting over your septic tank with highly aggressive roots plants and trees could erode the soil easily. That's why it is critical to know also what type of plants or trees you should avoid for.

The following are the plants that could harm your septic:

  • Clematis.
  • Any kind of bamboo family.
  • Cedars not including the dwarfs kind.
  • And woody vines.

Here are the top damaging trees you must avoid:

  • Willows.
  • Elm tree.
  • Birch tree.
  • Periwinkle.
  • Cotoneaster.
  • Silver maple.
  • Pachysandra.

How Do You Care About Your Septic System?

The septic system pumping service usually takes place every three to five years. Of course, some factors may directly or indirectly affect its maintenance overall schedule. This includes the following:

Emptying household septic tank

  • The size of your septic tank.
  • Number of people residing in the house.
  • And the frequency of water usage.

Considerations like how well your house's water piping system will have an indirect bad impact on your septic tank. For instance, unmaintained leaky pipes, particularly the toilet contributes as much as 200 gallons of water a day.

As toilet usage frequency contributes 25% -30% of your total household water use. This is equivalent to 70 gallons each person per single day of water consumption for an average single-family home.

Thus, taking care of your leaky pipes helps prolong the service cycle of your septic tanks.

Does Septic System Last Forever?

Septic tanks and sewage system

A modern septic tank has an average service life of 20-30 years. However, your drainfield relatively has a shorter lifespan of about 20 years only. This is because drainfield are more exposed to weather changes which affect them considerably.

Properly constructing your septic system plays a critical role in preserving the service life of your septic system. Therefore, you must comply with all standard building requirements to ensure your septic system lasts longer. 

To Wrap Things Up

You can certainly pour concrete into your septic lines or systems in general. As long you are abiding by all the standard safety protocols served by your local authorities, you'll be fine building a septic project.

In addition, just follow all our recommendations to ensure your septic project has the best structural integrity output. However, as always nothing beats the finished job quality of contracting an expert. So that's another vital takeaway you need to look after.

If you find this article helpful, please read as well our other related post below:

Is Comet Or Soft Scrub Safe For Septic Systems?

Can You Pour Concrete Over A Utility Easement?