Photograph of  a seepage pit collection at the factoryCESSPOOLS for onsite wastewater disposal - How do Cesspools Fail?

  • CESSPOOL FAILURE CRITERIA - CONTENTS: Criteria that define cesspool failure, How to determine that a septic cesspool is at or past its end of useful life, Soakpits & reed beds: life & failures, Comparing cesspools, seepage pits, drywells, soakpits
  • POST a QUESTION or READ FAQs about the definition of state of "failure" of a cesspool or soakpit

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This cesspool maintenance & repair article describes the criteria used to show that a cesspool has failed, or that a cesspool is at the end of its life and needs to be replaced. If a cesspool shows the conditions described below, pumping it out, aerating it (dangerous) or other cesspool service or cesspool maintenance procedures may be simply a waste of money and in some cases can be dangerous too.

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Cesspool Failure Criteria (MA)

When inspecting a cesspool or soakpit, how do we know how much capacity it has to handle sewage at a property, and how do we know when it is at or near the end of its useful life? The cesspool failure indicators listed below can prevent a property owner from wasting money pumping or otherwise "servicing" a system that really needs to be replaced.

If you insist on pumping out a septic system that is at the end of its life, the remaining period of use is likely to be quite short - the pumping cost might have been better spent towards replacing the system since an end-of-life cesspool is going to fill up again in just a few days of usage.

Failure Criteria for Cesspools [generally also applies as well to soakpits, drywells, and seepage pits]: If the waste level is within 12" of the inlet pipe near the top of a cesspool the system is at end of life and needs to be replaced. Some municipalities and experts will state other distances. In Massachusetts according to the Massachusetts Title 5 Septic Law the following are considered a failed or unacceptable cesspool installation:

A cesspool or soakpit needs replacement if it meets any of these failure criteria. While a septic company may offer to pump, partially pump out, or agitate or aerate the bottom sludge in the cesspool in an effort to extend its life, these procedures are potentially very dangerous (see Cesspool safety Warnings and at best will give only temporary relief.

Photograph of  a seepage pit collection at the factory Where a new cesspool or soakpit of traditional sort is going to be installed you should at least use a concrete pre-cast model with a safe cover (see photos at left and above).

Pre-cast concrete soakpits or cesspools are a safer construction than a site-built stone or concrete block soakpit or cesspit, but

Watch out: even a pre-cast concrete soakpit or cesspool is very unsafe if it does not have a sound and secure cover that protects from someone falling into the system. Details are at CESSPOOL SAFETY WARNINGS.

Fortunately there are alternative onsite wastewater disposal alternative designs which can handle limited or even zero-space sites, so a simple cesspool as a destination for blackwater is no longer the only choice for limited-space sites.

Reader Question: is this a cesspool? Has it failed? What are my repair options?

I came across your site while doing septic research. I recently had my septic tank pumped a few days ago. I noticed odors outside my home plus I heard gurgling when I flushed the toilet, as well. Last year, I had the tank pumped in October. I usually have it pumped every other year not every year.

I had a riser installed in 2003 to have easier access to the tank lid. This year, as well as last year, the water level was up into the riser and almost to the lid. My septic service said my leach bed quit working like it is suppose to and offered to have it repaired for around $6,000. Also, this person did not hose down the tank as it was being cleaned out. Is that something that should have been done?

With my best guess due to property size and location of everything, I would say I have a cesspool-type tank (my pipe comes out of the house and straight into the tank). I do not have room for a leach bed with pipelines that stretch out, plus, when I built my garage when I moved here, I would have came across pipes in the ground being that I had to dig 15 down into the ground about 30 feet away from the tank. I have lived in this house for 16 years. It was built in 1950. It looks like my tank is either 500 or 1000 gallons.

So, what are my options? Is it necessary for me to " shock" the septic system, being that I think I have a failed system? Should I add anything to the tank to aid in its effectiveness? - S.M., Pennsylvania, 10/12/2013

Reply: first figure out what is installed: differences between a cesspool & a septic system

A competent onsite inspection by an expert usually finds additional clues that would permit a more accurate, complete, and authoritative answer than we can give by email alone. That said:

First we need to get clear on what type of wastewater treatment is installed, as you are mixing terms;

A cesspool is a perforated site built or precast hole in the ground that disposes of effluent through the cesspool bottom (which quickly clogs so is not counted in the effluent dispersal area) and cesspool sides into the soil. Solids along with sewage effluent remain mixed together in the cesspool (unlike a septic tank and drainfield system).

A cesspool does not and cannot ever adequately treat the wastewater since at cesspool depths below the ground surface there is not enough oxygen for aerobic bacteria to live. (BIOMAT FORMATION & SEPTIC LIFE) But it can "dispose" of effluent into the soil. (The risk of discharging inadequately-treated wastewater effluent is contamination of nearby waterways or local aquifers by chemicals, salts, pathogens). For this reason, in some jurisdictions new cesspool installations are not permitted.

As you understand, a septic tank - a water tight container - is quite different from a cesspool. The septic tank accumulates solid waste while sending effluent out into a network of (hopefullly) more shallowly buried pipes that distribute effluent into the soil for final treatment and disposal. About 40% of treatment occurs in the tank, the rest in the soil.

Cesspool Cleanout & Rejuvenation

Hosing down the sides of a cesspool after pumping would be pointless; in fact pumping the cesspool is close to pointless too. Small solids leaving the cesspool mixed with wastewater clog soils around the system, first at the system bottom, then lower sides, then over time clogging progresses up the sides until the cesspool no longer leaches into the soil. Then the system is in failure and needs replacement.

Watch out: Cesspool rejuvenators try aerating the cesspool bottom and sides - using hydrojetting, not chemicals (chemicals also contaminate the soils and are illegal in most jurisdictions SEPTIC TREATMENTS & CHEMICALS).

This dangerous step can cause a site built cesspool to collapse - even causing fatalities, as my articles on this topic have documented at SEPTIC TANK ACCIDENT REPORTS.


For this reason most cesspool pumpers won't fully pump out an old site built system.

At best, cesspool pumping is a temporary band-aid giving a bit longer use of what is basically a failed system. Cesspool failures are defined in the article above. By your description it sounds as if your cesspool is in failure mode - you are just limping along with a failed cesspool.

What Can I Do When the Cesspool has Failed?

When a cesspool has failed, if there is room the property owner usually adds another cesspool daisy-chained downstream from the first one; If there is not even room for a second cesspool then the first unit may be excavated, soil removed as needed, and a new system constructed; but I suspect that on a very small site an owner may run into legal issues with the local building or health department as the site may not comply with local building and health codes.


There are alternative small-footprint wastewater treatment system designs such as those specified by Dr. Jantrania (Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross.). But before considering an alternative septic design one would need to employ a local septic design engineer who knows local soils, local laws, and who knows what local officials will accept.

Extending the Cesspool Life

If you install a new cesspool, and particularly if your household does a lot of lint-producing laundry, it may be worthwhile to install a filter at the laundry graywater discharge to keep that material out of the cesspool; minimizing flushing unnecessary grease down drains also helps.



This material is a chapter of our Septic Systems Online Book: That document explains septic system inspection procedures,defects in onsite waste disposal systems, septic tank problems, septic drainfield problems, checklists of system components and things to ask. Septic system maintenance and pumping schedules.

Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information in books or pamphlets for sale is reserved to the author. Technical review by industry experts has been completed; reviewers are listed below. Further review comments and content suggestions are welcome. Home buyers who want less technical advice should see the Home Buyer's Guide to Septic Systems.

Also see The Septic Systems Home Page.

This article is part of our series: CESSPOOLS which explains what a cesspool (or in the U.K. and in Australia & New Zealand, a soakpit) is, gives important safety and maintenance advice for cesspool systems, and defines the criteria for cesspool failure. We also provide critical safety warnings concerning cesspool systems as with some older and especially site-built cesspools there is a risk of dangerous collapse or cave-ins.


Continue reading at CESSPOOL AGE ESTIMATES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see these

Key Drywell & Cesspool Articles

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