Does a septic tank need to be covered with dirt?

Author: Miss Kimberly Bednar PhD  |  Last update: Monday, June 8, 2026

While you can typically add a bit extra topsoil to do things like level your lawn, if your septic tank is newly installed, any additional soil added to the top of your drain field can cause damage. Drain fields are designed with an appropriate amount of gravel and soil to ensure the system functions properly.

Should you cover your septic tank with dirt?

#4 Dirt Can Block Air Flow

Believe it or not, your septic system needs to breathe. Some lids have small vents that let gasses escape and keep the right pressure in your tank. If you cover these vents with dirt, you block the air flow.

How much soil should be over a septic tank?

Though it requires some strategic thinking, there are several benefits to landscaping your leach field. Putting something on top can mitigate erosion-—you want about 1-2 feet of soil over your pipes at all times. The right plants can optimize oxygen for the microbes in the soil.

What should I cover my septic tank lid with?

Plant tall native grasses with fibrous roots around the opening to conceal the tank lid from view. Place a light statue, bird bath or potted plant over the septic lid. Septic tank risers and covers are an alternative to concrete and blend into green grass.

Can I leave my septic tank uncovered?

No it needs to be closed to keep bacteria & heat going, in a proper working septic tank (not treatment plant) it takes five days for BOD biological oxygen demand on black water (crap) to break down and kill the bad bacteria while gray water (sink, bath, washing machine ) takes three days.

Understanding Septic Systems | Ask This Old House

Does a septic tank need to be covered?

Prevent Debris Entry: Lids keep out rainwater, debris, and other materials that could disrupt the tank's functioning or cause blockages. Regulatory Compliance: Many local regulations and health codes require septic tanks to have secure lids to ensure public health and environmental protection.

How long can a septic tank sit unused?

A standard septic system that was working properly and then not used for a period of time, such as 4 – 5 years, typically does not lose effectiveness or the ability to function properly once it is put back into use.

Should a septic tank lid be airtight?

A tight seal will prevent any liquids from entering or escaping your system. Water entering the system can be as dangerous as water escaping. If your septic system fills with water, the pipes can become blocked and the solid waste has no room to enter — a recipe for a sewage backup.

Can you put gravel over a septic tank?

Only add mulch directly above the septic tank

Also, avoid plastic sheets, landscaping fabric, gravel, or other materials. While they're an easy, good-looking fix, they limit soil airflow and water evaporation, disturbing your septic system.

Can you put anything on top of a septic tank?

In general, the EPA discourages building on septic drainfields, but there are a few things you can do that are generally considered safe. These can include open-air kennels for pets, lightweight swing sets, or small volleyball or badminton nets.

Can you add dirt on top of a septic drain field?

Reshape or fill the ground surface over the drainfield and reserve area. However, just adding topsoil is generally OK if it isn't more than a couple of inches.

How many gallons of water a day can a septic system handle?

The average residential septic tank can hold around 950 gallons of water. This number provides a rough idea of the tank's daily processing capability. According to the OSTDS guidelines, an average person is assumed to use 50 gallons per day, so a family of 4 may produce up to 200 gallons per day.

Can you put too much bacteria in a septic tank?

In some cases, yes. Too much of a good thing can cause problems. A septic system relies on the correct balance of bacteria to do its job. An overpopulation of bacteria can deplete the oxygen in the septic tank and turn the environment septic.

What are the do's and don'ts of a septic tank?

DON'T flush material that will not easily decompose, such as hair, diapers, cigarette butts, matches, or feminine hygiene products. DO conserve water to avoid overloading the system. DON'T wash or flush medicines or hazardous chemicals like paint, paint thinner and bleach into the system.

What happens if dirt gets in your septic tank?

Because Mud is a much thicker substance than typical water, it is much more likely to clog the pipes of your septic system. This leads to the drains of your house not working, or could even lead to unsafe water. Furthermore, pools of water may start appearing around a clogged septic tank, and it will smell awful.

Should septic tank lids be buried in the ground?

Don't bury the septic tank lid.

Always make sure the septic tank lid sits a few inches above the ground.

What will ruin a septic tank?

Septic Tanks Don'ts

Don't pour grease, oil, or fat down drains. Do pump out your septic tank every 3-5 years. Don't flush non-biodegradable items like wipes, feminine products, or diapers. Do conserve water to reduce strain on the system.

Can you pour a concrete pad over a septic tank?

The problem of finding space for a concrete patio and of concealing a septic tank are both solved by putting the patio on top of the septic tank.

What is the best ground cover for a septic field?

As for what you can plant over your septic tank and drain field, grasses (including ornamental grasses) often work best. Their shallow root systems are less likely to invade the septic system and cause damage. For the same reason, small, non-woody ground covers are a good choice.

Should a septic tank lid be covered with dirt?

While you can typically add a bit extra topsoil to do things like level your lawn, if your septic tank is newly installed, any additional soil added to the top of your drain field can cause damage. Drain fields are designed with an appropriate amount of gravel and soil to ensure the system functions properly.

What do you cover a septic tank with?

You can use almost any temporary, movable objects to cover your lids, like:
  1. Mulch (but not landscaping)
  2. Pea gravel.
  3. Removable bricks.
  4. Removable pavers.
  5. Removable stepping stones.
  6. Removable flagstone.
  7. River rock.

How do I keep my septic tank from floating?

Thankfully, there are anti-floatation measures that can be added to the system design plans. Perhaps the most basic is to use concrete, which weighs 85 pounds per cubic foot and can be added into the design in a few different ways. Some fiberglass tanks may also have an anti-floatation lip built onto them.

Can a septic tank go 20 years without being pumped?

In general, a septic tank should be inspected every 1 to 3 years and pumped every 3 to 5 years.

How do I reactivate the bacteria in my septic tank?

You can replenish good bacteria in your septic tank by adding three rotten tomatoes or 1/4 ounce of yeast every three months. Put three overripe tomatoes in the garbage disposal while running the faucet. Or pour 1/4 ounce of yeast in the toilet and flush it down.

How much does it cost to get your septic tank pumped?

The average cost to pump a septic tank is $423, with most people paying between $289 and $557. Septic tank pumping isn't the most glamorous task, but it's one that you should definitely stay on top of every three to five years to keep your system working properly and avoid an unsightly (and smelly) mess in your yard.

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