Going Off-Grid in the 21st Century – FAQ’s on Septic Systems

In the last two articles, we covered a few different options for dealing with waste water, namely a grey water system & composting toilet. By far though the most popular system out there is the septic system. It is even quite possible that if you own an older home in a city, or live in a rural part of the country that you are actually using one right now (some estimates are 25% of the population still uses septic systems). In this article we are going to take a quick look at what the system consist of, approximate sizing requirements, general maintenance, common issues, and options for those that live near the coast or in a wetlands area.

The Basic System & How it Works:

A basic septic system simply consists of a large concrete box with one or more chambers in it & a leaching field (aka drain field) generally composed of gravel. The waste from your house simply travels from your house out to the septic tank. The tank is sized to allow time for the solids to settle & allow for any grease or oil to float to the top – aka above the outlet pipe (aka the sludge & scum layers). The water & organic material (broken down via the anaerobic & aerobic process) that does make it to the outlet pipe is then distributed to the leaching field via some perforated pipes where nature gets to run its course. As the water leaches out of the pipes into the fields, the water then gets filtered as it passes through the soil until it gets to recharge the groundwater supply.

Sizing the System:

There are two main sizing factors that come into play – the size of the tank & the size of the field. The size of the tank is generally based on how many bedrooms are in the house & if the washing machine will be using it or a separate field (see Gray Water article). The size of the field is based on this & the results of a perk / soils test done by an engineer. With so many factors that do come into play and with some newer products the days of using a rule of thumb are gone. Today most of this will be dictated by your State’s Department of Environmental Quality or Health Department (Alabama RulesFind your State’s here). My only recommendation is you might land between 2 different sized tanks, if so, go with the larger one.

Maintaining your System:

Except for the occasional pumping, there really isn’t much else one needs to do with a basic system. Ahhh but do I really need to pump it out, I mean we never did at our family’s house, and we have had that for 10 or 20 years? Well yes you still need to; the catch sometimes is knowing when you need to have it done. But first let’s examine the “do I need to” part.  As you may recall from above the septic system contains a layer of sludge & scum which over time builds up. The biggest issue is if these layers grow enough and make it out to the leaching field. When this happens you are looking at some major issues & remediation costs.

So this leads us to the question of how often… I am sure you have heard some companies say once a year, while others say every 2, 3 or 5 years. Unfortunately just like the sizing of your system there is no real rule of thumb as it is based not only on your tank size, but how you use it. Inspectapedia has a pretty good chart that you could use as a baseline, but you should also consider the following;

  • Where does my washing machine water go to? Septic or separate area
  • Do you wash your clothes all on one day, or spread it throughout the week?
  • Do you use a garbage disposal? Yes or No
  • Does a family member have long hair which you are always cleaning out of drains? Yes or No
  • Do you use lots of bleach, vinegar, conditioners? Yes or No
  • Do you have any older style toilets (more than 1.6 gal a flush), older washing machines, dishwashers, or take really long showers? (Yes or No)

Depending on how many items were answered with the first answer, you should look at getting your system checked much sooner than the chart shows.  If you are trying to maximize your systems life, by reducing the amount of water, solids, & chemicals that go there the better your system will perform.

Enzymes, Yeast, and Bacteria:

While there is much debate about the usefulness of said products, I will simply have to side with the company that cleans mine out. “Generally they are not required in concrete systems as most of the needed bacteria, etc… are added naturally and the concrete aids in the process. For Poly tanks, it depends on usage and the system. In some cases (like mine) where bleach, vinegar, or other unknown items slowed down or killed off the bacteria – it would be wise to add them to get the process restarted.” When I asked about using Rid-X™, they said that it is a decent product but the catch is that there isn’t a date manufactured or best used by date on the packaging and it depends on where you buy them from; how quickly is the product moved from manufacturer to the shelves& how is it stored. As you can see by the picture, that is the product I used & I will find out in another two years how well it worked.

My system stinks:

Well of course it does, now get your head out of it. In all seriousness, if you are in your yard & can smell it, you need to have your system inspected & possibly pumped. If you are in your house, well you would be better off either calling a plumber, or making sure all your plumbing vents lines are open & water is in your P-traps.

When a Basic System won’t Work:

If you happen to own a small lot, don’t have the needed perc rate or soils, live near the wetlands or the coast, the chances of a basic system being allowed are pretty much nil. While I don’t live on a small lot, the size of my field was limited which ruled out gravel and required us to use an alternative “Infiltrator” system which came out to be around the same cost. For others though, you may be looking at macerating units, pumps, filters, aerobic systems & even specially designed above ground fields which are then covered with dirt. Needless to say if you have to go this route the prices are not only higher but you have to factor costs for yearly maintenance and electricity.

Additional Information & Websites: