Photograph of Don't fall into a septic tank - it's likely to be fatal.Septic Tank, Cesspool & Drywell Safety Warnings
Safety procedures for & warnings about inspecting, servicing, or working on septic tanks, drywells, cesspools

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InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

This document provides important safety warnings for septic systems and cesspools, and provides some safety suggestions for septic system inspectors, septic system inspections, septic pumping contractors, and home owners.

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SEPTIC & CESSPOOL SAFETY GUIDE - Septic System, Septic Tank, & Cesspool Safety Warnings

Providing inspection and diagnosis of on-site waste disposal systems is an extremely valuable public service which helps protect people from expensive unanticipated septic system repair costs and helps protect public health by assuring sanitary disposal of sewage and gray water waste from buildings.

More importantly though, septic system inspections may detect and warn about serious safety hazards at some properties.

The strong warnings issued below intend to reduce septic system safety hazards for inspectors and property owners/occupants, but it is not the author's intention to dissuade inspectors from providing this valuable service.

Watch out: Septic tanks, cesspools, and drywells present serious hazards including septic cave-in's or collapses, methane gas explosion hazards, and asphyxiation hazards. Simple precautions which we describe here can help avoid a dangerous or expensive septic problem.

The septic hazard news video at right recounts a child falling into a septic tank and a separate septic fall-in fatality.

Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved to the author.

Examples & Case Reports of Fatal Hazards at Open or Insecure Septic Tank, Cesspool, Drywell Covers

LARGER IMAGE-1 of a septic catastrophe - walk the site, find possible tank locations, don't step through the cover LARGER IMAGE-2 of a septic catastrophe - walk the site, find possible tank locations, don't step through the cover LARGER IMAGE-3 of a septic catastrophe - walk the site, find possible tank locations, don't step through the cover

Safety Warning: there is a very high risk of fatal falls into septic tanks, cesspools, or drywells: danger lurks at cesspools, open covers, tanks or tank covers in poor condition, and from high levels of methane gas CH4 or hydrogen sulfide H2S.

These septic system dangers include the risk of collapse, falling, asphyxiation, explosion, and other potentially fatal hazards as well as risks of unsanitary conditions such as bacterial or viral infections. This hazard is more than theoretical. We have personally assisted in investigation of several septic or cesspool fall-in fatalities and are aware of others.

Caravan site debris and site hazards (C) Daniel Friedman Caravan site debris and site hazards (C) Daniel Friedman

Inspecting a mobile park housing migrant workers at a New York farm, Steven Vemilye and Daniel Friedman documented various immediate and serious safety hazards at two open or semi-open septic tanks and cesspools. Shown above is a home-made dry-laid concrete block well (unstable) surrounding an open septic tank.

The property manager left the concrete septic tank cover off and just tossed a light section of plywood over the system in order to make frequent septic tank pumping easier. This mobile home collection was occupied by many families including families with small children. An adult or child falling into an open septic tank is very likely to die quickly.

Caravan site debris and site hazards (C) Daniel Friedman Caravan site debris and site hazards (C) Daniel Friedman

Above Mr. Vermilye, accompanied by the attorney who had asked us to perform a site inspection, was demonstrating the instability of the covers over septic facilities at this location. [As we document
at MOBILE HOMES, DOUBLEWIDES, TRAILERS, we report with regret that Mr. Vermilye passed away on 19 June 2001.]

Watch out: Readers trying to diagnose and deal with sudden soil subsidence or yard collapses should
see CESSPOOL SAFETY WARNINGS as those hazards can also apply to drywells and septic tanks, and


There can be other unexpected hazards when inspecting building sites and septic systems. In the photo series above, the author was inspecting the home shown from outside before looking in the crawl space to locate the main waste line exit point and thus before predicting the probable location of the septic tank.

Walking close to this house should have set off an alarm about possible unsafe conditions: poor maintenance, old home, of an age likely to have used a steel septic tank. In fact the author found the tank very quickly by stepping through its cover, avoiding serious injury or even possible fatality mostly by luck. It was throw myself sideways into the briars and garbage at the site or fall completely into the septic tank.

Reader Question: My parents' septic tank caved in and the basement smells

26 August 2015 Anon said [by private email]

I was checking your site and couldn't seem to come across my particular situation. Basically i'm curious. so my parents have a septic tank system for their house, and a few days ago it caved in. Right now the whole basement is absolutely putrid. There isn't actually sewage in the house, but I'm guessing the vapors or methane from a pipe are making it smell terrible, actually can't be downstairs b/c it smells so bad.

My question is about a sack of potatoes they have down there. They have been right next to the area that smells the worst, and I'm wondering if they are contaminated? I won't eat them regardless, but my folks think they will be fine? I just feel like the fact that potatoes have a tendency to "soak" up things, I wonder if this isn't really bad for them? Could you please elaborate for me? Thanks!

Reply: watch out for methane gas explosion hazards and bacterial hazards and septic tank fall-in hazards

Watch out: septic odors are likely to include methane gas; methane is explosive. If there is sewer gas in the home a spark could blow the place up. Your folks need expert onsite help and need the explosion warning immediately.

Watch out: if someone falls into a septic tank or into a collapsed one, the result can be a quick but ugly death. Rope off the area and keep people away until an excavator or septic contractor has made the necessary repairs.

I'm not sure what the potatoes would absorb nor what's in the basement but I wouldn't eat them either. The possibility of bacterial hazards is there.

Reader Followup:

... that's already all been handled professionally. This is after the fact, I just wanted to know if they had or could have been contaminated somehow? If so, how?

Reply: research on the odor, gas & chemical absorption properties of potatoes

Jeff, if there is a smell there is a gas present. If the potatoes smell then they've absorbed VOCs, sewer gases, possibly also they've been affected by airborne pathogens.

If you want only to address the odor and chemical absorption properties of potatoes please see these articles that discuss odor absorption and other properties of potatoes.

A Safety Guide for Septic System Inspection, Cleaning, Pumping, and Homeowner Care

Do not drive over the septic tank or septic piping

PHOTO of a septic seepage pit collapse when a truck drove over it.

Unless special provisions have been made such as protection of sewer piping and septic tanks from damage, vehicle-rated septic tank covers, or similar steps, do not drive vehicles over the septic system.

Driving over septic tanks, septic piping, or drainfields risks costly damage to the septic system and may also be dangerous.

The bulldozer in our photo (left) was called to help remove a truck which drove over septic system components leading to a surprise collapse.

If a septic line must be run under a driveway, for example to pass from a building to the septic tank, the line must be protected by choice of materials (schedule 40), or placed in a covered and protected trench at adequate depth (such as with concrete covers over the trench) to avoid damage.

If a septic tank is to be located below a drive or parking area, it too must be properly designed and protected from collapse.

A septic drainfield cannot be located below a driveway or parking area. Doing so will prevent proper drainfield operation due to soil compaction and also due to loss of proper evaporation of moisture through the surface, as well as almost certainly leading to crushed broken piping.

Question: safety & Health Procedures for Texas & other septic tank cleaning or pumping operators

2016/09/21 Jerry Herold said:

My son pumps out septic tanks in the Hill Country in Texas, for last 3 months. He has had pneumonia, and sicknesses, with days off. What type of protection is required to wear? Should this be of no cost, given by the employer? should there be available showers, clean clothes, shoes, face shield, waterproof gloves, etc, at no cost to the employee? He comes home in his work shirt and pants, using his private vehicle. is that permissible? must he shower and change before he leaves the work-site? Isn't he contaminating his vehicle, his house, his wife and his son, if does not shower and change at the work-site?

Reply: National & state workplace safety standards for septic tank pumping workers


OSHA publishes workplace safety standards for septic tank pumper / cleaning operators that address most of the questions you raise. You can download a copy of OSHA's septic tank service operator safety procedures and suggestions for workers entering and cleaning vessel (as in ship) sewage tanks as a free PDF here:

You'll see that although the OSHA document focuses on marine sanitation systems, the suggestions in that document address most of your questions as well.

Emergency contact information for OSHA: For questions or to get information or advice, to report an emergency, fatality, inpatient hospitalization, amputation, or loss
of an eye, or to file a confidential complaint, contact your nearest OSHA office, visit or call OSHA at 1-800-321-OSHA (6742), TTY 1-877-889-5627.

Methane Gas Hazards around Septic Systems, Methane Gas Toxicity vs. Methane Explosion & Asphyxiation Risks, How to Measure Methane Gas Levels

Methane Gas Hazards are primarily of explosion or asphyxiation - see METHANE GAS HAZARDS for details.

We commented above at Septic System Safety that methane gas which maybe encountered in septic system is both explosive and an asphyxiant.

A thoughtful reader, George Fielder, previously a salesperson for GfG Instrumentation, pointed out that these are the hazards. (We had inaccurately stated that methane gas was "toxic".)

Readers who need more details about the safety concerns regarding methane gas in and around septic systems should be sure to review the septic system methane gas hazards and measurement and references cited at SEPTIC METHANE GAS (also see Septic Methane Gaslinks listed at the "More Reading" links at the bottom of this article in this article)

Guide to Proper Abandonment of Un-used Septic Tanks

PHOTO of a septic seepage pit collapse when a truck drove over it.

It is important to properly abandon un-used septic tanks, cesspools, or drywells. If an old septic tank, cesspool, or drywell is simply "left alone" there may be very serious cave-in or fall-in safety hazards.

In addition to having been consulted in fatalities involving humans, we have learned that falling into septic tanks and cesspools is a risk for animals as well. In 2008 Mark Cramer shared a report from an owner that that their horse fell into a septic tank and died tragically before it could be rescued.

The collapsing septic tank was not in the location which the owners thought it would be found, and clearly it had an unsafe cover.

Properly abandoning a septic tank, drywell, or cesspool which is no longer in use involves at least the following steps:

  1. Locate all of the un-used septic tanks, cesspools, drywells on the property. At some properties there may be multiple systems and tanks, such as a chain of old cesspools or one or more septic tanks with a separate drywell. See these articles on finding hidden, lost, buried septic system components:
  2. Pump out the septic tank, cesspool, or drywell - a septic pumping contractor performs this step.
  3. Break open the tank bottom - so that it won't hold surface runoff, forming an un-wanted water or mud reservoir. If the septic tank is steel, often the contractor will dig out the tank, crush it, and then bury it back in the original hole. When we installed a new concrete septic tank the contractor buried the crushed steel one on edge alongside the new concrete tank.
  4. Fill in the septic tank, cesspool, or drywell, or hole where the tank was located (if you crushed an old steel tank) with stone, rubble, and soil so that there is on future collapse hazard.
  5. Document the location of the filled-in items so that future site work or building plans can avoid or at least anticipate these buried obstructions.
  6. If newer septic tanks, cesspools, or drywells remain in use at the property, be sure that their locations are documented (see SEPTIC TANK LOCATION SKETCH ) and that each of these has an intact, secure cover that will not cave in nor be easily opened by a child

    We've written elsewhere about the importance of keeping livestock off of septic drainfields and septic tanks. There may be an extra risk of livestock-caused septic tank collapse where old septic tank or cesspool covers or even new fiberglass septic tanks and covers are installed.

Septic System Safety Articles


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