A cesspit, often referred to as a soakaway or a closed tank, represents a critical component of rural and older urban wastewater systems. Essentially, it is a sealed underground chamber designed to temporarily store raw sewage before the liquid component slowly percolates into the surrounding soil. Unlike modern septic systems that separate solids and liquids within a single unit, a traditional cesspit functions primarily as a holding vessel, requiring regular emptying by specialized vehicles. Understanding the function, maintenance, and legal implications of these underground tanks is vital for any property owner relying on one.
How a Cesspit Functions in Wastewater Management
The operation of a cesspit is relatively straightforward, relying on gravity and simple retention. All wastewater from the property—whether from the toilet, kitchen, or shower—flows into the tank through a single inlet pipe. Because the tank is sealed, anaerobic bacteria begin to break down the organic matter, but the process is slow and inefficient compared to aerobic systems. The primary role of the chamber is to act as a reservoir, preventing the raw sewage from overwhelming the soil absorption field. Once the tank reaches capacity, the semi-liquid effluent must be removed to allow the system to continue functioning.
Key Differences Between Cesspits and Septic Tanks
While the terms are often used interchangeably by the public, there is a distinct technical difference between a cesspit and a septic tank. A septic tank is designed with baffles that separate the sewage into three layers: a scum layer of oils and fats, a clarified liquid layer in the middle, and a sludge layer of solids. The clarified liquid exits the tank to a drainage field for further treatment. In contrast, a cesspit lacks these baffles and does not treat the effluent; it merely holds the waste until it is pumped out. This fundamental design difference impacts the maintenance frequency and environmental impact of the system.
Environmental and Regulatory Considerations
Due to the risk of groundwater contamination, regulations governing cesspits have become increasingly stringent in recent decades. Modern environmental standards generally discourage new installations of traditional cesspits because they allow raw sewage to leak directly into the surrounding earth without any form of treatment. If a property does have one, it is usually classified as a "Decommissioned Well" or "Soakaway" in official records. Owners are often required to obtain permits and ensure the surrounding soil is suitable to prevent contamination of water sources.
The Necessity of Regular Emptying
Perhaps the most significant ongoing cost and responsibility associated with a cesspit is the need for regular desludging. Because the tank is a sealed unit with no outlet for the solid sludge, the accumulated solids must be manually removed. If the tank is not pumped out frequently—typically every three to five years depending on usage—the sludge will overflow into the soakaway area. This leads to blockages, system failure, and the unpleasant consequence of sewage surfacing in the garden or backing up into the home. Hiring a licensed tanker truck is the only safe and hygienic method for this process.
Signs of System Failure
Homeowners should be vigilant for specific indicators that their cesspit is reaching capacity or failing. The most obvious sign is the presence of foul odors, particularly around the inspection covers or in damp areas of the garden. Additionally, slow-draining sinks, gurgling toilets, or sewage surfacing in low-lying areas of the yard are clear warning signs. Ignoring these symptoms can result in costly repairs, environmental hazards, and the inability to use the property until the issue is resolved.
