How to Landscape Around a Septic Tank

Trying to figure out how to best landscape around your septic tank? Here’s where to start: decide between turf and native plants, install shrubs and trees at the right distance and use creative garden ornamentals to hide the tank’s access points.

In this article, we get into all the important septic system landscaping details and let you know if and how much you can dig (or add topsoil), how to deal with irrigation across the drain system, and where to place common hardscapes such as patios and decks.

1. Your septic system is a no digging, no tilling zone

Whatever landscaping you plan to do around the septic tank, if it requires digging and tilling, you’ll probably need to change the location or the idea.

Septic systems are no digging, no tilling zones which means:

• No installing fences with buried posts
• No digging for garden ponds or swimming pools
• No foundations for gazebos and other installations that require digging

Septic tanks and drain lines of the subsurface trench systems are sometimes as close to the surface as 6 inches, easy to damage by digging or tilling. 

There’s no adding thick layers of topsoil either. The soil above your septic system’s drain pipes is as deep as necessary to ensure proper airflow. It’s okay to add 1 or 2 inches of topsoil when planting, but no more than that. Otherwise, you can mess up the system and reduce its effectiveness and lifespan. 

Note: There’s more buried under your yard than the septic pipelines. Before digging, call 811 and check for underground utilities. Learn more about how to deal with buried service lines when landscaping from our guide: “How to Landscape Around Buried Cable Lines.”

2. Turfgrass is a “yes” with a footnote

Everybody loves lush, green lawns, and there are quite a few reasons that make turf a good choice for landscaping septic tanks:

• Grass has a high evo-transpiration rate, helping the soil eliminate wastewater more easily. 
• Its fibrous roots are excellent in keeping soil together and reducing erosion.
• Turf is also a safe option since its thin, shallow roots don’t dig deep enough to damage the drain lines. 

However, not all grasses are the same. To limit watering, mowing, and chemical treatments (fertilizers, herbicides) across the drain field, choose a low-maintenance turfgrass for your entire yard. Go for drought-tolerant turf adapted to your local climate and the yard’s sun exposure.

Here’s why: the septic system drains water faster than the surrounding area. If it works fine, the drain field will dry out sooner during drought spells and brown grass strips will start to appear above it. 

If this happens, don’t worry. Allow the grass to enter dormancy and avoid watering it unless the drought is prolonged. Adding too much water to the drain field can affect its function.

With some moisture always present underneath the soil, turfgrass over the septic system is generally greenest and thickest – the best grass in the entire yard. However, if you see green, lush strips of turf over the drain field while the entire lawn is heat-stressed, your drain field might be overloading. Reduce the wastewater flow from the house and contact a septic system professional for an inspection.  

These resources can help you choose the right type of grass:

• “Best Drought-Tolerant Grasses”
• “Best Shade Grass Seed”
• “Low-Maintenance Grasses as Grass Alternatives”

3. If you choose native plants, go with dry prairie species 

Native plants are low-maintenance, don’t require fertilizers, and rarely need herbicides. You will need to rake fallen leaves and cut dry flowers occasionally, but overall, it’s less work than growing turfgrass. 

Beth Clawson from Michigan State University Extension says that dry prairie species are the best native plants for septic systems.

“The roots of dry prairie plants do not clog septic system pipes because they do not thrive in water-saturated conditions. Avoid using any plants that require moist or wet soils. These plants seek additional moisture and will likely invade open pores and pipes,” explains Clawson.

Septic tank-friendly plants recommended by Michigan State University include three main categories:

• Sedges and grasses (little bluestem, prairie dropseed, June grass)
• Bulbs (daffodils, tulips, hyacinth, iris)
• Wildflowers (white aster, black-eyed Susan, lobelia, ferns, sweet woodruff)

You also can plant groundcovers, but choose less dense ones so the soil can still breathe and evaporate water properly.

Stay away from woody plants such as shrubs or trees. Their roots can easily damage underground pipes.

Pro tip: The septic tank needs pumping from time to time. Avoid plants with thorns, spines, or prickles on the accessways to the tank lids. Difficult access can increase the cost of septic tank maintenance.

4. Build the veggie garden 10 feet away

Vegetables often require more digging, watering, fertilizing, and overall care than other plants. If you plant them in the septic system area, you are exposed to foot traffic, digging, and a surplus of water that can affect its function.

Even more importantly, growing vegetables on a drain field is simply unsanitary. Household chemicals and bacteria from the wastewater can escape the filtration layers and contaminate the vegetable, exposing your family to diseases.

How far away should a garden be from a septic tank? If the yard size allows, leave 10 feet from the edge of the septic installation to the vegetable garden.

5. Don’t plant trees near the septic system 

Woody shrubs, bushes, and trees have deeper, thicker roots that can reach the drain lines and damage the system. Don’t plant them anywhere above the septic system. You can grow shrubs and trees in other areas of your yard as long as they are far away to keep their roots from reaching the septic installation. A basic rule of thumb says to plant:

• Bushes and shrubs at least 10 feet away from the septic system edge 
• Small trees with non-invasive roots 20 feet away or more
• Large trees at least 50 feet away.

Experts from the University of Georgia recommend using the tree’s mature height as the minimum planting distance from the septic drain field and adding more distance if possible. 

“For example, if you are planting a crabapple, plant the tree at least 25 feet from the nearest drain line; 50 to 75 feet would be even better.” 

Pro tip: Avoid water-loving trees such as willows, poplars, and cedars, actively seeking moisture through the soil. 

6. Only add mulch directly above the septic tank 

Don’t use mulch to cover the drain field. 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. 

However, you can spread mulch or gravel on the soil above the septic tank to help the lid blend better with the surrounding area. That’s if your septic tank is newly installed or the area around it hasn’t been planted.

Many septic tanks are completely underground and covered by lawn. They’re so well hidden that you need property plans to know where the tank is buried. If that’s the case, it’s your choice if you want to leave the tank lids masked by grass or redesign the area. Either way, add a garden decoration nearby to signal the lid and make it easy to spot when it’s time to pump the tank.

7. Find a better place for garden hardscapes

What’s a landscape project without a deck or a patio? These common outdoor structures add elegance and comfort to any yard but don’t have a place where a septic system is installed. 

They are compact, heavy structures that seal the soil and can crack subsurface pipelines because of their weight. Some models require intensive digging, which is a no-no for drain fields.

Also forbidden above the septic system area are:

• Pathways
• Gazebos
• Fire pits
• Outdoor kitchens
• Storage sheds
• Above-ground swimming pools
• Garden ponds
• Fences

You can install them outside the area. Leave 10 feet from the septic system to ensure you don’t damage drain pipes.

8. Redirect water away from the drain field

Experts from the IFAS Extension of the University of Florida explain that when more water moves across and down through the drain field, pollutants have less time to be filtered before entering the groundwater below. 

To prevent additional water from getting into the drain system, consider the following improvements when landscaping the surrounding area:

• Keep the gutter  downspouts clean to prevent roof water from flowing toward the drain field
• Regrade part of the yard to lead runoff away from the septic system area
• Install additional drainage, such as French drains
• Install (move) sprinkler systems so that irrigation water stays 10 feet away from the drain field.

9. Surround the septic system with protective borders

Heavy traffic leads to soil compaction and reduces the septic system’s effectiveness. Parking cars over the drain field, running heavy equipment, and heavy foot traffic can compromise the system.

Protect the septic installation by making its limits obvious and hard to pass for vehicles. Here are some ideas:

• Surround the septic system area with boulders
• Install a retaining wall or a fence
• Plant shrubs with non-invasive roots at least 10 feet from the septic installation

Don’t dig inside the drain area. Ensure fences or retaining walls are installed outside the pipeline zone.

Note: When working on borders, ensure easy access for septic tank pumping.

10. Hide the tank lids with garden decorations

You can’t plant shrubs to camouflage the tank lid, but you have other beautiful and creative options, such as:

• Decorative lid covers
• Hollow fake rocks (also fitted to lids raised a few inches above the soil)
• Bird baths
• Birds feeders
• Garden benches
• Barrel-like pots with plants
• Sun clock
• Tiered planter boxes
• Garden gnomes

Don’t use heavy materials or objects. You need to be able to move them fast when it’s time to service the septic tank. 

11. Leave a repair area 

Each septic system has a limited lifespan of 25 to 30 years, after which the soil becomes oversaturated, and you need to move the system to another spot in your yard.

That new drain field is known as a repair area or reserve area and in some states it’s mentioned on the OSS (septic system) permit. It’s typically the same size as the present septic system and has undisturbed, native soil. 

In this space, you should avoid planting or building anything that would be hard or costly to remove in a few years, such as large trees or an underground swimming pool. 

FAQ about landscaping around the septic tank

How close to a septic tank can I build a patio?

It’s best to leave 10 feet from the edge of the septic system to the patio, especially if the patio has a foundation that requires serious digging. 

How do you locate a septic system?

To locate the septic system in your yard, try these methods:

• Consult the local county records for your home’s septic system permit 
• Contact local septic maintenance companies to check if they know the location
• Look around the yard for visible tank covers or sand mounds
• Hire a professional to detect the septic system placement

How much weight can a septic tank support?

The weight a septic tank can handle depends on many factors (size, how deep it’s buried, material, etc.). For example, a concrete slab can support about 600 pounds per square foot. 

But you shouldn’t see its resilience as an invitation. Don’t put heavy materials or objects on service tanks, and always ensure easy access to the tank lids for servicing.

Call a professional landscaper!

Who better to help you choose suitable, beautiful plants to cover your septic tank? Find a local landscaping company through Lawn Love and give your yard a makeover today!

Main Photo Credit: Philipp Berezhnoy | Adobe Stock Free | License