How To Build A Dry Well Septic System

Installing a dry well for septic system is a common method of discharging gray water. In addition to the conventional systems, a septic system may have different types, such as chamber systems, sand filter systems, mound systems, and aerobic treatment systems. Dry wells and leach fields are two common aspects used in septic systems to discharge wastewater. Let’s find out more about these two options along with their characteristics.

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How Does a Septic System Work?

Sewage from the house passes to a septic tank through a pipe. Solid waste settles at the bottom to create sludge while the other less dense oils and fats float on the top as scum. Various microorganisms break down these contaminants in the water and feed on them. Then the remaining wastewater drains eventually from the septic tank into a drain field. Dry wells and leach fields are such examples of these drain systems. 

What is the Purpose of a Dry Well?

A dry well is a perforated tall concrete cylinder buried deep in the ground with gravel surrounding it. This is also known as a seepage pit, leaching pit, or leaching pool. This is one of the oldest and simplest methods used to dispose gray water. These modern Underground Injection Control (UIC) wells are also built with plastic and are even used to handle water from heavy rainfall. Some dry wells have a catch basin which is a temporary sediment trap that pre-filters the water before it enters the dry well.

How to Install a Residential Dry Well?

Installing a dry well in the wrong way will cost you expensive repairs and even fines. So, the best recommendation is to get it installed correctly by a professional. They will check the soil conditions, select the best location in your yard, determine the size of the well, and whether you need any catch basins. They will make sure that the dry well is not too deep to contaminate the underground water. They will also figure out the ideal dry well tank sizes for septic system. The advantage of getting professional installation is that you are in line with the regulations of the Environmental Protection Agency (EPA) and the local authorities. 

Dry Well Maintenance

There are a few important things to consider regarding the maintenance and repairs of a dry well. Dry wells have the risk of contaminating groundwater, especially in commercial properties that deal with hazardous materials. Dry well maintenance is recommended even in residential areas to make sure that the dry well lasts effectively for a long time. Sampling the soil on the outside is done for annual compliance. This could even be done with sediment and water samples from the dry well. Sampling is mandatory if the dry well handles chemical products.

What is a Leach Field?

A leach field is a land area that has long thin pipes running from the septic tank. These pipes carry the wastewater to the ground around them. There are holes in these pipes so that the wastewater seeps into the soil and moves down through the different layers consisting of sand and gravel. A leach field should have at least 50 yards to maximize drainage without impacting the groundwater supply. This soil absorption system is ideal for regions with large surface areas. But people living in confined spaces would not be able to have a leach field to discharge water

Dry Well VS Leach Field

As you are aware by now, a dry well is a single structure that discards water deep into the ground in one place. A leach field, in the contrast, is a wider structure with pipes running parallel to the surface to discharge the water. This is the most significant difference between the two options. However, at present, dry wells are not popular in septic systems as before. This is because it increases the risk of contaminating groundwater due to the large structure buried deep in the ground. Hence, this water discharge method is not approved by most local governments.

Although the leach field does not run deep as a dry well, it requires a larger area of land. It may not be the most convenient option for urban residents. Regardless of the structure, both are methods of waste and gray water disposal. Both methods carry water from a septic system to the soil either by passing water deep into the ground or discharging it over the surface.

Frequently Asked Questions

What Size Gravel for Dry Well and Septic System?

The ideal size for drain field rock is between ¼ inch to 2 and ½ inches. Gravel is the best choice as it can withstand large amounts of weight without being crushed. This allows it to support the weight of the septic tank and the rest of the system.

How Close to a Property Line Can a Dry Well Be?

A dry well should be installed at least 25 feet away from the foundations of a building and about 10 feet away from property lines. If not, you should have an approved impermeable liner installed at a suitable distance to prevent infiltration of discharge under these facilities.

What Happens When a Dry Well Fills Up?

Once a dry well reaches its full capacity, water will spill out over the side of the cup. This can happen mainly because dry wells get clogged easily with leaves and debris falling into line. So, make sure to keep the gutters and pipelines leading to the dry well clean to prevent unnecessary clogs in the system.

How Much Does It Cost to Install a Dry Well?

The average cost of installing a dry well ranges from $1,561 and $4,750. The prices vary depending on the size of the well, labor charges, and material. 


When comparing a dry well for a septic system with a leach field, there is no definite answer as to which is the better option. Since both systems have their pros and cons, it is up to you to decide which system suits you best. Call a professional to help you determine the best solution and how you can install it. You can also try some other water discharge methods to figure out various possibilities.

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