Septic Tank Know How

Septic Tanks

Sometime ago I wrote a post about cottage septic systems, it was back in the early days of this site, so I thought perhaps it would be good to update it a bit and repost considering how important a septic tank usually is to a cottage.

As with any of our posts, please consult a professional before attempting anything described here.

The Rules

It is very important that you consult with your local authorities before installing, repairing, changing or doing anything with your septic tank, septic disposal field etc. Rules for septic systems vary and are quite strict, fines for breaking the rules can be expensive. Obtain the required permits and authorizations before you start.

Gravity Type Septic Tank

I should mention is that there are several types of septic systems available today. For the most part, the type I am describing here are the “gravity” type septic systems. Those are the most basic and what you will likely encounter in cottages, especially older cottages.

Gravity septic tank systems usually consist of a drain pipe leading to a septic tank and several pipes leading from the tank to the drainfield.

As I said in my original post, after reading this, you may feel that I am full of crap….which might not be far from the truth.

However, I have had the unenviable pleasure of digging up the septic tank and the related plumbing, disposal field pipes etc, and feel I have a pretty good idea what is going on down there.

Once you dig up a septic tank, you never quite lose the flavor….or the scent….it stays with you a long, long time and the weird thing is, long after it’s gone, or you think it’s gone, it comes back again.


Before I get into this, I want to remind you septic tanks are dangerous business. The fumes and escaping gases can make you sick or kill you. You can fall into a septic tank and drown….yuck….or catch all kinds of diseases. I don’t recommend you start digging up your septic system unless you have a good reason and you should first consult a professional. They have the safety training and equipment to work on septic systems safely.

In fact, in most places the homeowner or cottage owner is not allowed to dig up the septic tank, that has to be done by a person certified to work on septic systems. That said, this information should help you to know what is going on in your cottage septic system and what can be done to fix it if something goes wrong.

What Happens When We Flush?

Have you ever wondered what goes on when you flush? Sure the effluent in toilets disappears to be replaced by some nice clean looking water, but what happens to the “stuff” you just flushed away in the toilet.  We all know that it goes away, down the drain and out to the mysterious tank in the ground, called the septic tank and disposal field.

Well, the effluent (stuff you flush) leaves the toilet and runs down the disposal pipe making it’s way underground inside the pipe until it meets the septic tank buried beneath the ground, usually behind your camp or cottage.

The Septic Tank

The “septic tank” is a fairly large cement, plastic, fibreglass or metal tank buried beneath the ground that acts as a receptacle and container for the effluent flushed from your toilet, or from your kitchen sink or bathtub etc.

Everything that goes down the drain, ends up in the septic tank by way of a “waste pipe” Septic tanks can hold 1000 gallons, although some are bigger, some smaller. It depends on the location, the size of the family, number of bathrooms etc, that would have gone into the original calculations to determine how big a tank would be needed.

If you need to get at your septic tank, be prepared to do some digging. Usually it can be done by hand, but it sure goes faster if you have a skilled backhoe operator do it for you.

Skilled backhoe operator is the operative word, because one mistake with the backhoe shovel and your septic tank could be damaged or destroyed. Not all backhoe and construction companies are certified to do septic system work, so check that out before you hire one.

The sewage waste pipe runs from the cabin to the tank, and usually joins the septic tank through the side where it empties into the tank. So it’s kind of like a miniature water slide running from the house to the tank…..everything slides down the pipe and ends in the big pool at the end. Yee-haa!! Look Ma No hands!!

The waste, or “effluent” as we like to call it, washed down the drainage pipe system from the toilet, splashes into the tank, with a delightful ‘plunk-splosh’ sound, that hopefully you will never hear because if you do, chances are it means you are inside your septic tank…not where you want to be at anytime. Let’s get inside and have a look around.

The solid stuff in the waste coming from the drain pipes, human waste, toilet paper etc,  floats for a bit, then settles to the bottom of the septic tank as it dissolves during the decomposition process. Most of it becomes liquid which makes up the bulk of what is in your tank. Brownish thick liquid….ooo-laa-laa….inviting eh?

A properly working septic tank has many microbacterial ‘thingys’ microbes, microscopic bugs, call them what you will, that are in the inside the tank, essentially eating the ‘stuff’ that enters the tank, breaking it down, which is how it becomes liquid.

Like the little guy in the pic, the septic tank microbes are waiting for you to ‘flush’ in order to get their supper. Any solids left over eventually sink to the bottom of the tank. Keep that in mind for later on in this post.

Three Layers

If you picture a cross-cut or side-on view of a working septic tank, you would usually see three ‘layers’ so-to-speak, the top is usually a thick scum like material going down a few inches, then comes the liquid layer, which is pretty much water and makes up most of the volume in the tank and the bottom layer which is made up of the solids that have sunk to the bottom.
septic tank sideview
On the opposite side of the septic tank from the sewage waste entry pipe coming from the cottage is another drain pipe leading out of the septic tank. You should see a “baffle” arrangement on the inside of the tank, in front of the place where the drain pipe is located.
The baffle is intended to stop the solids from entering the drainage field pipes before it breaks down. If the baffle is not there, solid waste and toilet tissue can come in the tank on one side and wash right out the other, where it won’t break down, at least not as it should, and will eventually clog the drainage pipes. You don’t want that….make sure the baffles are there.

Typically the drainage exit pipe only goes a couple of feet before it branches out at a “Tee” joint that connects it to two or three or more drain pipes. These are usually perforated pipe, 8-10 feet long or more, full of holes, which allow the exiting liquid to dissipate throughout what is called the “disposal field.”

The Disposal Field

The disposal field typically consists of gravel or small stones overwhich the perforated pipes are laid. Quite often these pipes will have material over them, called ‘socks’ which are designed to allow the drainage water to leave, but keep roots etc from getting into the pipes and clogging them up.

That’s really all there is to a basic septic tank system. Waste comes in on one side, microbes eat it up, the solids left over drop to the bottom of the tank, and the liquid remaining exits the tank through the drain pipe on the opposite side of the tank. From there it enters the drainage field where it disipates into the ground, and eventually makes it’s way back into the water table, hopefully clean.

What Can Go Wrong With A Septic System?

Septic systems are actually pretty straightforward and usually troublefree for years, however you can have problems with them on occasion.

The tank gets full of solids. Even if your system is ‘working’ properly, that is, the microbes are breaking down the solids etc, over the course of time, maybe even years, depending on the amount of usage, your tank will fill up with solids.

Once that happens, no more effluent can get in, and you have to have the septic tank pumped out. You call the local septic pumping company, and they come with a big vacumn truck, often called the “Honey Truck” The operator puts a big hose in the septic tank and pumps everything out. Yippee. If your tank doesn’t have a screw top for the hose, you will first need to uncover the tank and remove the lid so it can be pumped.

At cottages, because they are often not used everyday, a large septic tank can take a lot of waste before it needs to be pumped.

Septic Drainage Field Problems

However, what can happen in less time, is that the drainage field pipes can become clogged. Those are the perforated pipes I spoke of earlier.

These perforated pipes eventually can become full of solids, roots, soil, etc, which will stop the waste water from draining out of your tank. This is a common problem with cottage septic systems.

Your tank is actually OK, it’s the drain pipes that are not working anymore. If that happens, the easiest thing to do is dig the pipe up and replace them with new perforated pipe wrapped in the “socks” I mentioned earlier. It’s work, but it isn’t the end of the world. Forget about trying to get the stuff out of the existing pipes, chances are it is so tightly packed inside that the only way to get it out involves breaking the pipe.

Related to the above, and often a very easy fix, except for the digging up the tank, is that something gets tangled up in the entrance or exit pipe baffle.

For example, toilet paper gets in the tank and before it starts to break down, it gets in around the exit baffle, creates a dam or a jam, so to speak, and liquid cannot get out. Usually this means you just have to clear that clog and things will go back to usual.

Drain Pipe Clogs

The drain pipe from the house to the tank can also become clogged or choked with something. This can happen if toilet paper or another object goes down the toilet or other drain and fetches up somewhere on the way to the septic tank. In that case, sometimes a plumbers snake can push it through to the tank, or even pull the offending blockage back, or break it up so the water flows again.

You should have a ‘cleanout’ somewhere in the pipe system where you can put a plumber’s snake, or you might have to take the toilet up from the floor. I do not recommend using a liquid sewer cleaner like you might use at home to clear a blocked toilet or pipe, they can damage the septic system microbes. Sometimes it pays to call a plumber…..

Your tank is not working.

In other words, the solids are not breaking down in the tank. If you dig your tank up and look inside, (carefully, do not fall in or lean over the tank, and try to avoid sniffing the fumes, the gases can be deadly) and see a lot of toilet paper and effluent floating around, the tank may not be working.

This can sometimes happen early in the cottage season if the tank hasn’t been used for a long time. Not enough microbes at work. There are products you can purchase to add microbes to the tank, but I do not recommend them. Usually the tank will start to work as soon as you start using it again.

At our place we are pretty careful about what goes down the drain. Some cottagers don’t put toilet paper in the toilet, however we do, trust me, I cannot get into the habit of TP in the garbage. So far, it hasn’t been a problem. However things like cigarette butts, coffee grounds, food waste, etc should not go into the septic system.

Septic Tank System Treatments

Personally, I don’t believe in adding a lot “septic system treatments” to our septic tank. In most cases they are not needed, and in some cases can actually be harmful to the microbes and bacteria that are hard at work breaking things down in your septic tank.
I’m sure that there are folks who disagree, but I have not had much luck with that stuff. If it sounds too good to be true, or too easy, it likely is to good to be true. Septic treatments that claim to ‘clean’ your septic system will likely kill the microbes that you need to break down the solids. True, the treatment will probably do that, but then it becomes necessary to continually add more of the chemical ‘treatment’ which has by then, essentially replaced the naturally occurring microbes.

Kitchen Waste

It’s also not a good idea to allow kitchen sink waste water to go into the septic tank. In some places, cottagers have ‘grey water systems’ that are mini septic systems that take the drain water from the kitchen sink, bathtub etc. Grey water systems and tanks installed to accept kitchen and shower waste water are not legal in many areas so check with your local plumbing inspector before you install one.

Unfortunately, some soaps, dish soap in particular, that is high in anti-bacterial action, can harm the microbe bacterias working in your septic tank. For that reason, we do our dishes in a plastic dishtub that fits inside our kitchen sink, then throw the dirty dishwater out on the grass. It grows great grass….

The Green Green Grass of Your Septic Field

Speaking of grass, if you notice that grass is growing really well above your septic disposal field or tank, it can be a sign that the tank or pipes have a problem and the effluent is escaping too quickly. Might mean that it needs to be dug up and inspected.

Don’t allow trees or bushes to grow above your septic tank or drainage field. The roots will grow into the drainage pipes and even the septic tank looking for water and damage your system. The only thing above the tank and drainage field should be grass. Don’t park vehicles or anything else on top of your drainage field as their weight will compact the soil which will interfere with proper dispersal of the waste water leaving the septic tank.

Use Caution Around Your Septic Tank

Anytime you dig up a septic tank or the drainage field, remember the flumes can be deadly and you risk serious danger, such as passing out and falling into the tank, not to mention being exposed to all kinds of nasty things like bateria and germs. Keep that in mind, and for any serious problems, call in an expert who has been certified and licensed to work on septic tanks and disposal systems.

You should also be cognizant that old septic tanks can actually rot and collapse over the years, particularly old steel tanks that have been in the ground for a long time. The tank covers can collapse and you can fall into the tank and DIE, a most inglorious death. Old tanks should be replaced or pumped out and filled in with clean fill when you install a new system.

Be Aware of Septic Tank Laws and Regulations

You’ve been warned. Also remember in most places there are laws and regulations etc around everything you do to a septic system. Make sure you follow them, these days the fines can be frightening.

One more tip…if you do have to dig up your septic system, or have it dug up, make sure you mark it with a rock or piece of pipe or something driven into the ground when it is covered over again. If you do that, it will save you a lot of digging the next time as you will know exactly where it is located. Memories fade…I have missed mine by a foot or two, resulting in a lot of extra digging.

If you have bought a new or new to you cottage, ask the previous owner to show you where the septic tank is located etc. It’s not enough to know where the drain pipe leaves the cottage, the tank could be a foot or 10 feet from the building, the previous owner should have some idea of it’s location.

When to Pump Your Septic Tank

As I mentioned earlier, when to pump out a tank depends on usage and the size of the tank. I don’t think the typical cottage needs to be pumped every year, but it might, depending on how big it is. If you start to smell the septic system when you are outside, it can be a sign that it may need to be inspected and perhaps pumped. Or if you toilet seems to flush slowly, backs up, or if your shower drain backs up or doesn’t drain as quickly as usual.


In conclusion there are a couple of points to remember, septic tanks can be dangerous to work around, the fumes can be overpowering, there are diseases, and finally there is always a danger of falling in and drowning. So keep that in mind.
Also, while I have described a basic septic system, there are many variations both old and new. Your particular cottage septic tank system may be different than I have described although the basics will likely remain.

Whenever you go mucking around in your septic system, my advice is consult a professional first.

septic tank slogans
Clipart courtesy of Webweaver”s Free Clipart

One thought on “Septic Tank Know How”

  1. Hi,

    Very Good post, you’re obviously knowledgeable about all this stuff!!
    However, this bit…… “Your tank is actually OK, it’s the drain pipes that are not working anymore. If that happens, the easiest thing to do is dig the pipe up and replace them with new perforated pipe wrapped in the “socks” I mentioned earlier. It’s work, but it isn’t the end of the world. Forget about trying to get the stuff out of the existing pipes, chances are it is so tightly packed inside that the only way to get it out involves breaking the pipe.”

    Have you ever tried having the pipes cleaned out with a high pressure water jetter?
    We do this for folks all the time, we very rarely have to renew the drainage field. Doing this along with a quick drain camera inspection annually, or as required will significantly extend the life of your system…. much like your car, if you never service it, its gonna break down!

    Hope this helps for if you ever have any more trouble in the future


    Sam Foss

The Online Magazine About Cottages, Camps, Outdoors

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