How Do Drywells Work? Suffolk County, Long Island, NY

How Do Drywells Work?

What’s A Drywell?

A drywell is an absorption system burried under ground usually in the shape of a cylender. Drywells cylendars are usually a tall with concrete with holes in the side and an open bottom. (see bottom right side)

Drywell Installations & How They Work

Drywells are installed by digging a deep hole, usually near the septic tank, and setting the drywell in it. Gravel is usually dumped around the outside of the drywell and a lid put on top. The drywell is then connected to the septic tank with piping and the whole thing is covered with soil. Effluent enters the drywell from the septic tank and then exits out the holes in the side and seeps into the soil that surrounds it.
Drywells were also constructed of brick. These were built as upside-down cone shaped structures constructed inside a large hole. Once completed, they were carefully covered up with soil (backfilled). Some have small lids at the top of this cone. This lid is often accessible from the ground surface for pumping, visual inspections or just gazing into for sheer delight. Dry wells are drainage structures that leach rain water from parking lots, roads, buildings, roof water, bridges, or a house roof or driveway into the ground. Home dry wells can also be utilized to leach laundry water into the ground. They can consist of precast concrete ring or multiple rings depending on the capacity needed or the depth which is needed to reach good sand for sufficient drainage. These precast rings are made in different diameters that also effect drainage capacity. On top of the precast ring or rings is a top which can be a dome or a slab with a smaller access hole in it. That hole is covered with either a steel manhole cover and brought to grade for access or a concrete cover that is buried below ground. If the cover is below ground, it will eventually need to be accessed at some point in it's life for maintenance.

Dry wells are very similar to a cesspool with two key differences. One difference is obviously what waste water it's being used to leach. The second difference is in the way they are maintained. Dry wells receive garbage, bottles, foliage, sand, salt, car parts, animals, concrete, bricks, and anything that rain water can flush into a drainage system. This can build thick layers of garbage on the bottom which can quickly backup the dry well and start flooding issues. Dry wells require a specific type of industrial vacuum truck to service these drainage systems. These trucks can suck up concrete blocks, bricks, dry dirt, heavy mud a few feet thick. They are very expensive and complicated machines that require a lot of maintenance and knowledge to keep them running. Where cesspools require a different type of custom vacuum truck to service cesspool and septic systems as well as grease traps. These trucks suck water, floating scum, and sludge from the bottom. 

Some cesspool trucks are capable of reversing their pump to blow air in a utilize the process called aeration. Parking lots can have one dry well or a thousand dry wells depending on the catchment area. Catchment area is the square footage of a roof, parking lot, roadway, parking garage that the dry wells were installed to serve. There are formulas we use to design drainage systems that consider catchment area and rainfall. On Long Island dry wells are a very common way for industry, commercial business, and municipalities to manage rain water runoff usually in combination with a system of catch basins. Some roadways, buildings, apartment complexes, home developments utilize sumps to retain then leach very large amounts of water. Sumps can be used in conjunction with drywells, catch basins, and other types of drainage systems.

Please contact:
Murphy's Cesspool & Septic Tank Service today for all your Drywell repairs or service needs.
Email: Service@NYSeptic.com Phone: 631.758.4171 | 631.476.5484