Septic Tank Management

Homeowners are responsible for maintaining their septic systems.  It not only protects the investment in your home, but also protects your water supply and those of your neighbors.  You don’t want to be the cause of major ground water or surface water contamination because of a malfunctioning septic tank.  The liabilities are potentially huge and your homeowners insurance may not cover you if you didn’t do the required maintenance.   It will also make selling your home difficult,  I personally have walked away from houses I wanted to buy because the septic system was not in proper working order.

Septic tank management can be very simple. If the tank has been properly constructed and installed very few interventions will be necessary and the interventions will primarily be inspections.  The major components of a septic system are a collection pipe from the house, the holding tank, and the drainage system (usually a field).  The collection pipe is the final pipe leaving the home that contains all the household waste water.  This part of the system is identical for people connected to a municipal sewer except for where the pipe goes.

The septic tank is a storage tank to separate out solids from the waste water. They are watertight and are usually underground.  They can be made of concrete, fiberglass and some plastics.  They are typically two chambers, the first one is to allow for large solids to settle and there is a baffle preventing floating scum and grease from entering the second chamber. The two chambers can be in the same tank or in multiple tanks.

Septic Tank Diagram: (Image Source http://www.cmhc-schl.gc.ca)

The tank allows for some breakdown of the solids through anaerobic breakdown of the organic components.  At this point the sewage treatment is a living process and it needs to be treated as such.  Killing these bacteria will kill your treatment process, and increase the amount of pollution you release into the drainage system and the environment.

Septic System Diagram:(Image source http://www.cmhc-schl.gc.ca)

After the septic tank, water is discharged into the drainfield for further treatment by bacteria in the soil and filtering from the soil itself. The water is pushed along into the drainfield every time more sewage enters the tank. It can be pushed by gravity or by a pump depending on the design.  If the drainfield receives too much water (rain and melt water included), it will flood, causing sewage to pool on the ground surface or backup into the house plumbing fixtures.  Overloading also prevents proper treatment of all the wastewater, so not only will there be a lot more water, it will be of a much lower quality.
Many jurisdiction require a reserve drainfield.  It is an area suitable for a new drainage system if your current system fails. Treat this area the same as your existing system.

Many areas have inadequate soils for groundwater dispersal.  An alternative system will be needed in this case.  Other reasons you may need an alternative system is if there are too many septic systems in one area or the system is too close to the water table or to surface waters.  Alternative septic systems use more technology to improve treatment processes. They will most likely need special care and maintenance. Some alternatives use sand, peat, or plastic media in the place of natural soil to improve treatment. Other options are to use artificial wetlands/lagoons, aerators and disinfection devices but these will be covered in another article.

Some Notes on Drain-fields, DO NOT drive on or park vehicles on top of your drain-field.  Anything that compacts the soil will prevent the dispersal of waterwater into the soil.  ONLY plant grass on your drain field.  DO NOT plant trees with aggressive roots anywhere near the drain field, the more aggressive the plant the farther away it should be.  DIVERT rain water away from the drain field, to prevent flooding and sewage backups into the house.

Annual inspections are essential. Spotting a problem early is a lot cheaper to repair than waiting until it is a catastrophic failure of the system. This can be on the order of hundreds of times cheaper.  Things that should be checked when inspecting your system are:

  1. Check the Sludge level.  It should be lower than six inches from your outlet.
  2. Check Scum Blanket depth. It should be higher than 12 inches from the outlet.
  3. Check operation of any valves, pumps, floats and back-flow preventers.  A lot of systems are built to be gravity powered, this is ideal because they are simpler (no pumps) and cheaper (no electricity).
  4. Check for leaks into and out of your tank.
  5. Check for lines of very green or burnt grass in the drainage field.

The most common maintenance on a septic tank is periodically they will need to be pumped out.  The more solids that get added into the tank the faster the sludge will build up.  Garbage disposals and people using the toilet as a garbage can (condoms and tampons are the leading culprits) lead to a lot of sludge build up.  Avoid putting anything that can’t or wont decompose easily into your septic tank, it will just need to be pumped out later, and if there is a pump in your tank it will get clogged with sludge and YOU will have to clean it out.   The scum blanket builds up fastest when people pour grease down the drain. Grease will eventually block your entire system if it is not kept in check.  Do not pour grease down the drain.  It is not good for the septic system or for a municipal sewer system…just don’t do it.

There are additives that claim to prevent the need for pumping, treat these claims cautiously.  They may work as advertised, or they may not.  I have never needed to use an additive in my septic tanks.  If you keep the solid loadings low, the pumpings will be few and far between.

Wherever possible avoid putting non organics down the drain. In my article on liquid waste management I talked about the dangers of toxic liquids disrupting the biological treatment processes.  If the biological treatment gets disrupted, the treatment drops to zero.  This could be from cleaners, paints (even latex), disinfectants, oils and the list goes on.   Remember to educate your guests as to the rules for septic tanks, many people are not aware they need to treat them differently.

That sums up your basic septic system maintenance.  Remember to keep as many solids and greases out of your septic system along with anything disruptive to the biological treatment process.  Inspect for leaks in the system and pump it out when necessary and your system will have a very long life.

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20 thoughts on “Septic Tank Management

  1. I was once called out to find a septic tank as part of a sewage survey. I pulled the van onto a disused corner of the yard so that I didn’t obstruct the drive and promtly lost the 2 front wheels as the top of the septic tank collapsed! I got out of the van VERY CAREFULLY!

  2. i intend to construct a residential septic tank at my house, The residence shall be for around 12 people can you assist me with the dimensions i can use at the same time i will be using borehole water from the same area, this plot is 5 archers. i will be grateful with your assistance

    • I would be happy to help you. First is I have a question, the 12 people. Is that the total number of residents or did you inflate that number to cover guests? It is a good rule to increase your numbers by at least half when designing the system. Second, I guarantee that there are many very specific bylaws, laws and regulations around septic systems where you live, find out what is legally required/allowed and a lot of your questions will be answered. That leaves the tank size. This link shows the guidelines for tank sizes, and like I said, inflate your numbers to covers guests. http://inspectapedia.com/septic/tanksize.htm
      I hope this helps.

  3. Pingback: How Big Of A Septic Tank Do I Need? | The Ωmega Man Journal

  4. we rent some fields which have a septic tank located near our two stables. The tank serves a total of three properties and a workshop toilet. We have a terrible problem with seapage from the septic tank manhole cover (it seaps through the lid, which is not secure fit) during recent high levels of rain – the whole immediate area around the manhole is flooded and smells horrendous – our problem the residents keep saying “it is just water” we are having major issuses with them and our two horses won’t even walk through the area as they too can smell it our vet has sais it poses a health risk to both horses and us alike as we have no other option but to walk through it to reach our stables and storage shed. What are the risks? and what can we do to ensure they carryout their responsibilities?
    any advice would be appreciated.

    • This is an excellent question about an unfortunate situation. There is definitely potential for health risks to yourselves and the horses. In general septic tanks should never overflow like you described.
      Look into who is responsible for building codes, and who is responsible for pollution abatement monitoring. Here in Ontario, Canada I would call the municipality, the local health authority and the Ministry of Environment for more information and/or to report the leaking tank.
      First, what is needed is an inspection. To determine what is wrong.

  5. Pingback: Septic Tank Alternatives: Lagoons and Constructed Wetlands | The Ωmega Man Journal

    • They are usually behind the home, but that isn’t a guarantee. It is definitely on the side of the house with the drainage field.
      The pipes will be hard to find as they are most likely plastic. Look in the basement to see where the drain pipes exit the house.
      The tank will be within one or two meters of the house. There may be a slight (or significant) raise to the lawn.
      Another thing to look for is a change in color of the grass. If you live somewhere that gets snow the snow over the tank will usually melt first.
      I hope that helps.

  6. I had my 50 year old system pumped out recently because it backed up into the house. It had never been pumped before…yet it functioned with no other problems until now. Now there is water standing at the edge of the hole where they dug the tank. What is this?

    • A 50 year old system may be at the end of it’s life depending on the construction material. Water on the surface at the hole is one of two things. It is either that the tank is leaking or that the soil is compressing and surface water is pooling there. The easiest way to tell if it is surface water or not is when it appears. If the weather is dry and the pooling is still present then the water is likely from the tank. If the water is from the tank it will also smell, and the grass will be greener or burnt around the water. With an old tank like that, it may have been cracked a long time ago but the sludge (which you just removed) was blocking the hole and now it can flow freely.

  7. we had some pooling in the yard about 30 feet from the septic tank , had tank pumped out and it started filling back up with clear water from drain pipes, dug up drain pipes to look for problem and cant find anything wrong could you please give us an idea what it could be?

  8. i have a 23 year old field.just had the tank sucked out and it was givin a thumbs up(60 years old). is there something can pour into the “field pipe access” to help the field out?

    • Best is to flush water through it. There are chemicals you can add but aren’t needed in most cases. Check with your local regulations to find one that is legal if you really want to add one.

  9. at my house we are having issues with the septic, we have pumped it out, but the toilets are not flushing, they over flow, and junk comes up in the bath tubs blackish muddy, stinky water, and they are not draining right either, we snaked them all the best we could. what are your suggestions on a diagnosis of what is wrong…

    • It sounds like your tile bed is clogged. Water can enter the tank from the house but it can’t be disposed of on the other end. Have someone inspect that part of the system.

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