Should You Get a Septic Tank for the Cabin?

Thinking of getting a small septic tank for your cabin, but unsure how septic systems work? Read all about them here, and then decide for yourself.

When I built the cabin in the woods where my wife, daughter and I now live, I knew creating a proper waste treatment system would be a big deal. Unlike in the city, where sewage is directed into a centralized treatment facility, rural life almost always involves figuring out your own way of dealing with waste.

That’s where septic systems come in. Almost all rural properties with indoor plumbing have some sort of septic system. Understanding how they work can help you make an informed decision for your cabin or vacation home. Here’s what you need to know.

Types of Septic Systems

Conventional Septic System

All septic systems include a large plastic, concrete or fiberglass receptacle called a septic tank buried some distance from the home or cabin. A large underground pipe connects the tank to the home’s drain system.

In a conventional septic system, waste water and solids flow through the pipe into the tank, where they’re partially broken down by microbes. When the partially treated liquid reaches a certain level, it flows out the other end to be distributed into the soil, often through a series of perforated underground pipes. Then it’s slowly purified by more microbial action.

The combination of pipes and soil is called a drainage field, field bed or drainfield. A proper septic system harnesses microbial action, but nearly all septic systems accumulate waste faster than the microbes can break it down. That’s why vacuum truck pump outs every couple of years or so are necessary.

Holding Tank System

In a holding tank system, the waste remains in the septic tank until it’s full. Then it needs to be pumped out by a vacuum truck. Holding tanks systems are much simpler and cheaper to install than conventional systems. But you’ll have to pay to empty them regularly, and that should be factored into your cost calculations.

Mound Septic System

When my wife and I hired a septic installer to put in our system, he took a quick walk around our wooded property and told us we had to go with a mound system. He explained that bedrock was too close to the surface for a conventional system, which needed deeper soil drainage.

A mound system is similar to a conventional septic setup, except the tanks and field bed are buried in soil trucked in and heaped into a “mound.” This type of septic system is necessary when the existing soil isn’t deep enough (as in my case), or it’s the wrong type of soil for waste water to percolate through properly (like clay).

Benefits To a Cabin Septic Tank System

  • Properly designed and maintained septic systems allow a comfortable, fully modern lifestyle no matter how far you are from the nearest municipal sewage treatment plant.
  • Conventional and mound septic systems can last for 40 or 50 years if they’re properly designed and pumped out by a vacuum truck every couple of years. Holding tank systems can last a lifetime.
  • Well-maintained septic systems are environmentally friendly, using no electricity and generating no pollution.
  • No monthly sewage bill.

Drawbacks To a Cabin Septic Tank System

  • Expensive and troublesome to install.
  • Need ongoing pump outs by a vacuum truck every couple of years for conventional and mound systems, and typically every few months for holding tank setups.
  • The more waste water and solids generated, the more burden placed on the system.
  • Eventually even the best built and maintained septic systems fail and may need to be completely rebuilt.

Installing a Septic Tank System

Unless you have an excavator, a loader tractor and plenty of experience and expertise, you’ll need to hire a professional septic system installer to design and build your system. It won’t be cheap, either. Most septic professionals I know charge from $9,000 to $15,000 or more for a full system installation, depending on the type of system and how much dirt needs to be moved.

It’s theoretically possible to install the septic tank part of the system yourself, as long as you have the heavy equipment needed to dig the hole and lift the tank. But I wouldn’t recommend it. It’s a precise job and any mistakes are going to be expensive.

Alternatives To a Septic Tank System

Composting Toilet and Gray Water Pit

If the only waste water leaving your home comes from showers and sinks, you don’t need a full-blown septic system. A gray water pit, for wastewater that doesn’t contain toilet contaminants, is a hole in the ground with gravel or mulch. Depending on environmental regulations in your area, that will probably be all you need.

And a good composting toilet allows for a comfortable bathroom experience without the trouble of a septic system.

Outhouse and Gray Water Pit

Wooden outhouse at a cabin in the woodsChristoph Hetzmannseder/Getty Images

If you’d prefer to keep your cabin rustic, a well-built outhouse is a great way to do your business with minimal trouble. As with the composting toilet, use a gray water pit for all the rest.

Words of Caution

The Danger of Trees

If you’re installing a septic tank and field bed for your cabin, there’s a good chance trees will be nearby. Be sure to cut down all trees near your septic system. Otherwise, there’s an excellent chance they’ll send roots into your pipes to absorb the nutrients in your waste water. Tree roots can cause the untimely and expensive demise of your septic system.

Too Much Toilet Paper

Even perfectly build septic systems can’t handle the reckless use of toilet paper you can get away with if your home is attached to city sewage.

If you opt for a septic system at your cabin, avoid using overly long strips of toilet paper. In my experience, any unbroken strips longer than four squares can get caught on the tank inlet, build up over time and eventually cause a blockage. Trust me when I say that resolving such a situation is not fun.

Robert Maxwell
Robert Maxwell has been a passionate DIYer since the mid-1990s, when he received his first childhood tool set. His rural upbringing gives him a lifetime of experience in all things DIY, from carpentry and fine woodworking to welding and vehicle repair, all of which he practices regularly from his self-built cabin in the woods in Northern Ontario, Canada. Robert has been a regular contributor to Family Handyman since 2020, where he writes from firsthand experience on a surprisingly wide variety of DIY topics.