A stone soakaway cesspool is one of several methods used to manage wastewater or drainage around a property. Although the words soakaway, cesspool, septic tank and sewer are sometimes used together, they do not all describe the same type of system.
Understanding the difference is important before building, repairing or replacing a wastewater system. The correct design depends on the type of wastewater being handled, the soil, groundwater conditions, available space, local building requirements and the number of people using the property.
What Is a Stone Soakaway?
A stone soakaway is an underground drainage area designed to allow liquid to slowly disperse into suitable surrounding soil. Traditional soakaways may be constructed using stone, gravel, masonry or other approved drainage materials.
The purpose is not simply to create a hole and fill it with stone. A properly designed soakaway must provide enough drainage capacity for the expected amount of water while also taking the surrounding ground conditions into consideration.
Soakaways may be used for rainwater drainage, treated septic effluent or other approved drainage applications. A system intended for sewage must be designed differently from a simple rainwater soakaway.
Stone Soakaway Cesspool
Soakaway vs Cesspool: What Is the Difference?
A soakaway and a cesspool should not automatically be treated as the same thing.
A soakaway is primarily designed to disperse liquid into the surrounding ground. A cesspool or cesspit is a pit used to receive wastewater. Depending on the design and local regulations, a cesspool may require pumping or may use surrounding soil for disposal.
Modern wastewater systems generally provide more treatment and control than older cesspool designs. This is one reason homeowners should understand exactly what type of system is installed on a property before repairing or modifying it.
How a Septic Tank and Soakaway Work Together
A septic system usually separates wastewater treatment from wastewater disposal.
- Wastewater enters the septic tank from the house.
- Solids settle inside the tank while lighter materials may rise toward the surface.
- Liquid effluent leaves the tank through the outlet.
- The effluent is dispersed through an approved drain field, seepage system or soakaway where permitted.
The septic tank therefore performs an important separation and treatment function before liquid reaches the drainage area.
For additional information about septic systems, visit the U.S. Environmental Protection Agency septic systems resource.
Cesspool vs Septic Tank vs Sewer
These systems all manage wastewater, but they work differently.
Cesspool
A cesspool is an underground pit or chamber that receives wastewater. Older systems may allow liquids to move into surrounding ground while solids remain inside. Because treatment is limited, cesspools may present environmental or groundwater concerns when poorly located, overloaded or improperly maintained.
Septic System
A septic system normally uses a tank to separate and partially treat wastewater before effluent moves to a separate disposal area. The system must be sized and installed according to site conditions and applicable local regulations.
Public Sewer
A sewer system carries wastewater away from individual properties through underground pipes to a treatment facility. Properties connected to a public sewer generally do not require their own septic tank for normal household wastewater disposal.
How Is a Stone Soakaway Constructed?
Traditional stone soakaway construction can vary considerably. The exact dimensions should never be selected from a general internet article alone because ground conditions can be very different from one property to another.
A typical construction process may include excavation, preparation of the pit or drainage area, installation of suitable stone or gravel, construction of supporting masonry where required, connection of drainage pipes and protection against soil entering and clogging the drainage material.
The system must also be positioned so that wastewater does not create problems for buildings, neighboring properties, wells, groundwater or nearby waterways.
How Deep Should a Soakaway Pit Be?
There is no single depth that is correct for every soakaway. Depth and overall size depend on several factors, including soil permeability, groundwater level, expected wastewater volume, local regulations and available land area.
Some traditional Jamaican construction projects use deep stone pits, but a particular measurement should not be treated as a universal requirement. Before excavating a large wastewater pit, the site should be assessed by a qualified local professional familiar with the soil and current building or environmental requirements.
Why Soil Conditions Matter
A soakaway depends heavily on the surrounding soil. Water must be able to move away from the drainage area at a suitable rate.
If the soil drains too slowly, the soakaway can fill faster than the ground can absorb the liquid. This can cause wastewater to back up or appear at the surface. Ground that drains extremely quickly can also require careful evaluation because wastewater may reach groundwater before receiving adequate treatment.
For this reason, soil testing and site evaluation are important parts of designing a wastewater disposal system.
Signs of Soakaway or Septic Problems
A properly functioning system may operate quietly for years, but several warning signs can indicate trouble.
- Slow-draining sinks, showers or toilets
- Wastewater backing up inside the building
- Unpleasant sewage odors outside
- Wet or unusually soft ground near the soakaway
- Wastewater appearing on the ground surface
- Gurgling sounds from plumbing fixtures
- Grass growing unusually green over one section of the wastewater system
These symptoms should not be ignored. A failing wastewater system can become both a property problem and a health concern.
Can a Stone Soakaway Last for Many Years?
Yes. A well-designed soakaway can remain useful for many years, but its lifespan depends on construction quality, soil conditions, the amount of water entering the system and how well the septic tank is maintained.
If excessive solids, grease or other unsuitable materials reach the drainage area, spaces between the stone and surrounding soil can gradually become clogged. Once drainage performance is seriously reduced, repair or replacement may be necessary.
Stone and Gravel Used in Drainage Systems
Clean, durable stone or gravel is commonly used in traditional drainage systems because the spaces between the aggregate allow liquid to move through the drainage area.
The exact stone size and construction method depend on the system design. Material containing excessive fine particles, soil or debris can reduce drainage performance because the smaller particles can fill the spaces between the stone.
Stone Soakaway Construction in Jamaica
Stone soakaways and other onsite wastewater systems have been used for many years in Jamaica, particularly in areas without a convenient public sewer connection.
However, construction methods that worked on one property should not automatically be copied on another. Jamaica has areas with very different soil, rock and drainage conditions. One site may have highly absorbent ground while another may have clay, limestone, shallow groundwater or other conditions requiring a different solution.
Property owners should also consider the location of buildings, property boundaries, wells, water storage systems and neighboring properties before deciding where a wastewater system should be constructed.
Watch the Stone Soakaway Construction Video
The video below provides a look at traditional stone soakaway construction and discusses some of the practical considerations involved in building this type of drainage system.
Important Safety Considerations
Excavating a deep soakaway or cesspool is dangerous work. Unsupported soil can collapse without warning, and old septic tanks, cesspools and wastewater pits can contain hazardous gases.
Never enter a septic tank, cesspool or deep wastewater pit. Excavation, structural support, wastewater connections and system design should be handled by qualified workers using appropriate safety procedures.
Frequently Asked Questions
What is a stone soakaway?
A stone soakaway is an underground drainage area containing stone or gravel that allows suitable liquid to disperse gradually into surrounding soil.
Is a soakaway the same as a septic tank?
No. A septic tank receives and separates household wastewater. A soakaway or drain field may then receive liquid effluent leaving the septic tank.
Is a cesspool the same as a septic system?
No. Traditional cesspools generally provide less wastewater treatment than modern septic systems. A septic system normally includes a treatment tank and a separate effluent disposal area.
What causes a soakaway to fail?
Common causes include poor soil drainage, excessive wastewater, clogged drainage material, solids escaping from a septic tank, unsuitable construction or groundwater conditions.
How deep should a soakaway be?
There is no universal depth. The correct dimensions depend on soil, groundwater, wastewater volume, site layout and local construction or environmental requirements.
Can rainwater go into a septic soakaway?
Generally, roof and surface stormwater should not be directed into a septic wastewater disposal system because the extra volume can overload the system. Rainwater drainage should be designed separately where required.
Final Thoughts
A stone soakaway cesspool can be part of an effective drainage or wastewater solution when it is properly designed for the property. The most important point is that a soakaway, cesspool, septic tank and public sewer are different systems and should not be treated as interchangeable.
Before constructing or modifying a wastewater system, consider soil drainage, groundwater, system capacity, safety and local requirements. Good planning at the beginning can prevent expensive drainage and sewage problems later.