Dry Well vs Leach Field – What Is the Difference?
Indoor plumbing is perhaps the most significant advantage of modern living when it comes to pleasant, sanitary conditions in the home. The ability to flush human waste down the drain with the push of a handle helps keep our houses clean, cozy, and odor-free.
But that waste doesn’t magically disappear when it is flushed – it has to go somewhere.
Septic systems deal with waste after being flushed away from a home or small business in areas not connected to a sewer system. Several septic systems styles include:
- Conventional systems (the most common type)
- Aerobic treatment systems
- Chamber systems
- Sand filter systems
- A sump pump and effluent drainage pipe
- Drip distribution systems
- Mound systems
- Evapotranspiration systems
- Constructed wetland systems
How Septic Systems Work
Here’s how a septic system works: sewage leaves a house through a pipe that leads to a septic tank. Solid waste sinks to the bottom of the catch basin, forming sludge, while oils, grease, and fats float to the top, forming scum. Microorganisms break down the sludge and some of the contaminants in the water.
The leftover wastewater is eventually drained from the septic tank into a drain field. There are several types of drain fields, including drywells and leach fields.
Dry Wells for Drainage
A drywell, sometimes called a seepage pit, is a hefty concrete cylinder perforated and surrounded by gravel that’s buried deep in the ground. The wastewater piped into a dry well is disbursed over a large area through the perforations in the well.
What Is a Leach Field?
A leach field consists of long, thin pipes that run out of a septic tank, carrying wastewater into the surrounding ground. These pipes are lined with holes so that the wastewater seeps out into the soil, sand, or gravel surrounding the pipes in the drainfield.
A leaching field and soil absorption system are good in areas with a large surface area but can struggle in a confined space compared to normal waste water sewage. A leaching pit needs to be spread out over at least 50 yards to maximize drainage and not impact the ground water supply.
Dry Well vs. Leach Field
The significant difference between a dry well and a leach field is that a dry well is a single large structure that runs deep into the ground, while a leach field is a series of pipes that run parallel to the surface.
Currently, dry wells are not installed in septic systems as often as they once were. Because a dry well is buried deep underground and is typically a large structure, it runs the risk of contaminating groundwater, which most local governments ban.
On the other hand, a leach field does not run quite as deeply as a dry well or septic drain field. However, it takes up a much larger area because the leach field is spread out parallel to the ground – not vertically like the dry well.
The dry well and the leach field are two engineering solutions to the problem of waste disposal and gray water. Both carry wastewater away from a septic system to be processed and decontaminated in the soil system. One (the dry well) simply does so by running deep into the ground with a single structure, while the other (the leach field) uses multiple smaller networks that run parallel to the surface.