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Underground Injection Control (UIC)

Large-Capacity Cesspools

On this page:

This page will help you:

  • Determine if you have a large-capacity cesspool
  • Understand why large-capacity cesspools are banned
  • Learn how to properly close your large-capacity cesspool
  • Find alternative ways to ""Cesspools are constructed below the ground surface. Sanitary waste enters near the top and percolates through an open bottom and porous sides.dispose of your sanitary waste

What is a cesspool?

A cesspool is a shallow system for disposing of sanitary waste. Although structures vary, most cesspools consist of a concrete cylinder with an open bottom or perforated sides. Sanitary waste from toilets, sinks, and washing machines enters the cesspool and percolates out the bottom. 

What is a large-capacity cesspool?

EPA defines large-capacity cesspools as:

Residential multiple-dwelling, community, or regional systems (e.g., townhouse complexes or apartment buildings) that dispose of sanitary waste, or
Non-residential cesspools that have the capacity to serve 20 or more persons per day (e.g., rest areas or churches) if they receive solely sanitary waste. (40 CFR 144.3)

The definition of “large-capacity” may vary from state to state. For example, some states define large-capacity cesspools based on the amount of waste or the volume capacity of the cesspool. Check with your permitting authority for more information.

EPA does not regulate the cesspools of single family homes or those of non-residential facilities that serve fewer than 20 persons per day and dispose of solely sanitary waste. However, these smaller cesspools may be regulated by state and local governmental agencies (e.g., departments of health).

Cesspools of any size that receive waste other than sanitary waste (e.g., from commercial or industrial processes) are industrial wells and are subject to regulations. 

Answer these questions to determine if you own or operate a large-capacity cesspool.
Questions: If your answer is yes: If your answer is no:
Residential Properties    
1. Do you own or operate a multiple-family home (duplex, townhouse complex, apartment building, or cluster development)? Go to question 3. Go to question 2.
Non-Residential Properties    
2. Does your building have bathroom facilities with the capacity to serve 20 persons per day? Go to question 3. You are not affected by the rule.Stop here.
3. Are your bathroom facilities connected to a municipal sewer? You are not affected by the rule. Stop here. Go to question 4.
4. Do your bathroom facilities drain to a holding tank, and is the waste in the holding tank disposed of off-site? You are not affected by the rule. Stop here. Go to question 5.
5. Do your bathroom facilities drain to a septic system (that is, a septic tank with a leach field) or package plant? (See note below) You are not affected by the rule. Stop here. You may be disposing your sanitary wastes into a large-capacity cesspool.

Note: If you are not sure where your wastewater goes, use dye or smoke tests to help locate the discharge points from your bathrooms and kitchens. Your local health department, a plumber, or licensed septic tank pumper may be able to help you determine where your sanitary waste goes.

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What is not a large-capacity cesspool?

Onsite waste disposal systems that have a buried tank, an effluent (wastewater) distribution system, and a soil absorption area and receive solely sanitary waste are considered to be septic systems. Large-capacity septic systems are regulated by EPA. Visit the Large-Capacity Septic Systems page to find out if you have one and to learn how to meet the requirements for these systems.

Why has EPA banned large-capacity cesspools?

EPA has banned large-capacity cesspools because untreated sanitary waste from cesspools can enter ground water and contaminate drinking water sources. This is a concern for the following reasons.

  • Cesspools are not designed to treat sanitary waste.
  • Cesspool wastewaters often have higher levels of nitrates and coliform bacteria than are allowed in drinking water.
  • The wastewater may contain other pollutants such as phosphates, chlorides, grease, viruses, and chemicals used to clean cesspools.
  • Areas of the country that rely on cesspools are more likely to rely on ground water for their drinking water supplies. Contaminants from cesspools could flow into this ground water.

What are the requirements for closing large-capacity cesspools?

EPA banned new large-capacity cesspools on April 5, 2000. Since that date, no new large-capacity cesspools may be constructed.

A ban on existing large-capacity cesspools went into effect on April 5, 2005. If you have not yet closed your large-capacity cesspool, you must do so immediately. EPA’s regulations require you to close your large-capacity cesspool in a way that ensures no contaminants could move from it to underground drinking water sources.

Contact your permitting authority to find out if there are any additional requirements you must meet. In closing your large-capacity cesspool, you must do the following.

  • Write to your permitting authority at least 30 days before you close the large-capacity cesspool.
  • Contact the authority and ask what information you must provide. You may be asked to:
    • Fill out a pre-closure notification form
    • Inventory form, or
    • Write a letter saying that you plan to close the cesspool.
  • Permanently plug or otherwise close the cesspool in a way that is approved by the permitting authority and that ensures ground water is protected.
  • Dispose of or manage any soil, gravel, sludge, liquids, or other materials removed from your cesspool or the area around your cesspool according to all federal, state and local requirements. Your permitting authority should have information about specific requirements in your state.

Review and download a copy of the pre-closure notification form.

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What are my options after I close my cesspool?

Some disposal alternatives to large-capacity cesspools are shown below:

  • Sanitary sewer hookup - Contact your local sewer authority about the possibility of connecting your home or building to the sewer system. Often, a sewer system hookup may be available even though it was not an option when your home or building was constructed. Because municipal wastes are treated and disposed of properly, sewer hookup is the best option for you and the environment. However, it may be an expensive option.
  • Holding tanks - Store the sanitary waste in a holding tank, which is then periodically pumped out for proper disposal of the waste. You can reduce the amount of wastewater that has to be stored by conserving water (e.g., using low-flow shower heads and low-flow toilets).
  • Large-capacity septic systems - Contact your permitting authority about the requirements for installing a large-capacity septic system (that is, a septic tank with one or more leach fields). Large-capacity septic systems provide some wastewater treatment. Note that large-capacity septic systems are regulated as Class V wells, and you must contact your permitting authority prior to constructing one. 
  • Package plants - Small wastewater treatment systems, known as package plants, are designed to treat limited sewage flow. These plants use prefabricated steel tanks and hold the wastewater for a longer time as part of the treatment process. You must get permission to build and run a package plant. Your permitting authority can refer you to the appropriate state or local agency. In addition, you may be required to remove certain contaminants from the waste before discharging the treated waste into the environment.

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