How deep do septic lines need to be? from research notes while working in construction: Septic drainfield trench depth specification:A typical septic drainfield trench is 18 to 30 inches in depth, with a maximum soil cover over the disposal field of 36"; or per the USDA, 2 feet to 5 feet in depth.
Typically, the drainfield consists of three to five trenches that are 18 to 24 inches deep, up to 100 ft long, with a perforated pipe in 12 to 18 inches deep gravel covered by 12 inches of soil.
Generally speaking, septic drain lines are buried between 18 and 36 inches underground, and the pipes are surrounded by gravel and sand to aid in the filtration and water treatment process. Some septic drain lines may be buried just 6 inches under the ground.
So how do tree roots get in a septic drain field, to begin with? There are a few ways this can happen. One is obvious – you planted them there. The takeaway of this entire article should be this – you should never plant trees near or in leach fields.
The best way to look for and locate the septic tank field lines is to look for humps in the earth where the dirt settles and that way you can discover the septic tank field lines. There is also a septic tank locator that can help to locate the septic drainpipes.
While the terms are often used interchangeably, a leach field typically refers to the specific area where effluent is discharged into the soil, whereas a drain field encompasses the entire system of pipes and distribution components involved in wastewater dispersal and treatment.
To find a buried sewer cleanout, walk around the perimeter of your house, close to the foundation. A buried sewer cleanout is generally located on the outside of a bathroom. You'll recognize it as a 3-to-4-inch capped pipe with a square or round head.
In addition to the potential contamination from pathogens, crops grown above your drainfield may also be exposed to household chemicals that are still present in effluent before it filters through the drainfield. Many of these are not safe for your septic system, let alone safe for human consumption.
Plant grass or keep existing native vegetation. These are the best covers for your drainfield. Direct all surface drainage away from the septic system. Use shallow-rooted plants (see plant list above).
Never add additional soil over the drain field unless it is a minimal amount used to restore an area that may have been eroded or pulled up by removing another plant. Try not to be overly zealous when tilling the soil for planting. Remember that the drain lines may be as close as 6 inches from the soil surface.
While a properly maintained drain field is designed to last up to 50 years, it's not likely that it will last much longer than that. If you're experiencing symptoms of drain field failure and you know that your drain field is getting up there in age, it might be wise to begin to budget for a drain field replacement.
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.
For instance, residential sewer line depth ranges from 18 to 30 inches. However, city sewer line depths are different. Your city's sewer lines must always be deeper than the deepest residential pipe to allow waste to flow downhill. As such, these lines can go as deep as needed.
Wet Or Soggy Areas
If you see dead grass and the ground is wet or soggy, especially when it hasn't rained, that's not good either. This usually means the wastewater isn't being absorbed and filtered through the soil properly, making the surface too wet – it's a sign your septic system might be leaking.
A septic tank's distribution box (or D-box) is a container (typically concrete) that receives the septic tank effluent and re-distributes it into the network of attached drain fields and pipes. To put it simply, its job is to evenly distribute the wastewater into the leach field.
Grass clippings, when allowed to remain around the drain field, can create a compost layer that impedes the soil's ability to treat effluents effectively. It's important to mow your lawn so it doesn't deposit clippings on the septic area and to bag or mulch your clippings to prevent them from washing into the system.
How Deep Is a Septic Drain Field Buried? Leach field lines are buried three to four feet below the surface during installation. The drain field system is surprisingly large, usually nearly 100 feet long, and each pipe is buried five to six feet apart.
However, if you are careful, you can put trees with non-invasive, shallow roots in the area around your drain field and septic tank. Some examples include crabapples and white oaks. It's best to skip the Japanese maple, as these are extremely well-known for their pipe clogging abilities.
Large animals also cause compaction. If you choose to allow animals to graze the drainfield area, you risk decreasing the effectiveness of you septic drainfield. Animals should never be allowed to graze the drainfield during the wet season and should be removed before grazing results in bare soil.
Aerobic and anaerobic bacteria in your septic tank “eat” the solid waste, leaving behind wastewater. Because anaerobic bacteria don't need oxygen, they are most common in the septic tank, whereas aerobic bacteria are more common in the drain field.
In order to keep your septic system running properly, you should avoid building on or near your leach field. While it's important to follow state and local building codes, plan to break ground at least 10 to 20 feet from where your leach field is buried.
Sewer cleanouts are typically 6 inches to 3 feet deep.
Household septic tanks are typically pumped every three to five years. Alternative systems with electrical float switches, pumps, or mechanical components should be inspected more often, generally once a year. A service contract is important since alternative systems have mechanized parts.