What Size Septic Tank Do I Need For a Tiny House?

What Size Septic Tank Do I Need For a Tiny House?

5 min read

If you’ve ever built a tiny house, you’ll know that there’s a lot that goes into it. From paneling to electrical work to structural design. But, perhaps, most importantly, in this modern age: plumbing.

Tiny homes typically require a 500 to 1,000-gallon septic tank. Though, it’s not always possible to implement a tank of this size. In some states, for example, the minimum tank size is 1,000 gallons. There may be exceptions to this rule if your home is on wheels.

I’ll cover everything you’ll need to know about choosing the right septic tank for your tiny home.

 

What’s A Septic Tank?

For starters who don’t know what’s a septic tank is (you can skip this part if you already know) it’s basically an underground chamber that helps in holding the wastewater until its treatment. It can be made of glass, plastic, and even concrete.

You can opt for the one that’s as per your requirements, but it’s important to get the services of an expert for the installation purpose. Plus, you can also ask for all the relevant information. Basically, a septic tank is holding the waste material and making your life easier in your tiny home.

It’s possible to get it installed and you can opt for the one that you prefer the most for your tiny home.

 

Factors That Affect the Size You’ll Need

1. Water usage

Some households use less water than others, so carefully monitor your water usage to get a general idea of how big of a tank you’ll need. I’ll explain how to figure out the exact size you’ll need, later on in this article.

 

2. Number of bedrooms

More bedrooms correlate to more people and, therefore, increased water usage. Therefore, septic tank size typically increases as a result.

 

3. Number of occupants

The more people you have living in your house, the more water you will have flowing through your system.

 

4. Size of house

Bigger houses usually need a bigger septic tank, as they tend to have more sinks, bathrooms, etc.

 

5. Zoning regulations

Regardless of how much water your household actually uses, many states put minimum requirements on tank sizes. Check-in with your local building department to see if your county has specific laws about this.

 

What Size of Septic Tank Is Suitable for Your Tiny House?

First, you need to determine the size of your tiny house. What’s tiny for you might not be tiny for anyone else. You have to consider the number of bathrooms too. You probably would have heard about the tiny house movement. So if you are all about downsizing, you would be thinking of the septic tank size.

When getting the septic tank for your tiny home, you have to keep the regulations of your region in mind. A tiny home can be anywhere between 100 sq ft to 400 sq ft. It can also be up to 500 sq ft. but again it depends!

 

A general rule of thumb is:

  • If you use less than 500 gallons a day, you’ll need a 900-gallon septic tank.
  • If you use less than 700 gallons a day, you’ll need a 1200-gallon septic tank.
  • If you use less than 900 gallons a day, you’ll need a 1500-gallon septic tank.
  • If you use less than 1250 gallons a day, you’ll need a 1900-gallon septic tank.

 

If you’re unsure about your water intake, here’s how to estimate by bedrooms:

  • A 1-2 bedroom house will usually require a 750-gallon septic tank.
  • A 3 bedroom house will usually require a 1000-gallon septic tank.
  • A 4 bedroom house will usually require a 1200-gallon septic tank.
  • A 5-6 bedroom house will usually require a 1500-gallon septic tank.

 

The installation specialist can give you the correct information. It’s important that you familiarize yourself with the relevant rules and regulations of your place.

 

How Does The Drainage System Works In A Tiny Home?

Now that you have heard enough about the septic tank and the tiny homes, you would be thinking about the drainage system in the tiny homes. The purpose of a tiny home is to make it portable as it reflects your lifestyle too. So not many people invest in expensive drainage systems.

Thus, that’s where the septic tank comes into play.

You need to dispose of the urine and feces properly as you don’t want to invite any issues to your tiny home. With the help of septic tanks, it would be possible for the solid waste to decompose.

 

How Does the Septic Tanks Works In Your Tiny Home?

Now that you are aware of the relevant capacity, you would be thinking about the science behind the septic tanks. In fact, with the help of such a system, it’s possible to live in such a tiny space and not care about going to the washroom. You need not see the jungles again and again!

Your tiny home has drainage pipes. These pipes would be around your house and would lead to the outside. It’s also possible that the drainage pipes would lead underneath. The drainage pipes are connected to your septic tank. So the septic tank is collecting all the waste. The waste pipe separates the floatable material that remains in your septic tank. The liquid passes into the soil.

Let’s say you want to install the septic tank in your tiny home. It’s best to get the services of an expert so that you can avoid all the hassle. You have to get information about the building permit and a contractor can help you with the entire process.

 

What Material You Should Select for Your Septic Tank?

Since there are different options available to you for the septic tank, you could be thinking about what type of material you should choose.

Consider the following:

 

1. Concrete

If you plan to go ahead with the concrete material for the septic tank, you should bear in mind that it would be heavy. Plus, when you are going with the concrete material, it can occupy too much space. It can be costly too! You can expect the cost to be up to $1000. However, it’s available with a lifespan of 40 years so that’s a good thing.

 

2. Fiberglass

When you are considering the fiberglass material for your septic tank then you can take advantage of its lightweight feature. Again, the lifespan is expected to be 40 years and the cost can be up to $1600. It’s better that you discuss your options with the professional service provider.

 

3. Steel

It’s also possible to get steel material for the septic tank. Although you can opt for the steel, the life span is 20 years. There are also chances of rust so you have to keep your relevant options in mind. You can expect the cost to be up to $1000.

 

4. Plastic

You might like this option as it’s lightweight and comparatively installing it would be cheaper for you. You can expect the cost to be up to $1000 and the life expectancy is 40 years.

When you have similar costs for various options, you can be confused as to what to consider. It’s better to ask the professionals to give you the best recommendation.

 

What to Keep In Mind When Getting A Septic Tank?

You can keep the following tips in mind when getting a septic tank for your tiny house:

 

1. Plastic septic tanks are a good option

If you don’t want to go through the installation process all by yourself then it would be a good idea to hire a professional. It’s always better to consider an expert for such services.

 

2. Septic tanks are not a one-size-fits-all

You have to select the septic tank size as per your requirements. Depending on the number of bedrooms you can opt for a suitable option.

 

3. Plan where it will go

There is limited space in a tiny house so the location of the septic tank matters too.

 

4. They can smell

It’s important that you are also considering a vent pipe for your tiny home especially if you don’t want to sit in a filthy odor. Installing a vent would thus be a good idea.

 

5. You may have to pay for installation

There is a cost of installation for the septic tank. It depends on your location and whether you are hiring labor for the job or not. There are tons of articles and tutorials available online, but it’s better to let the experts deal with the issue.

Getting a septic tank for your house with the right capacity can help you in many ways. You have to see what viable options are available for you. Make sure you make the most of your time! Get a septic tank that’s suitable for your requirements and you can definitely talk to a professional about such services.

 

Victoria Miller

I'm the founder of NTT. I live in Miami, Florida, and enjoy learning everything there is to know about tiny spaces.