Small Septic System For RV: Here’s How To Build One

What is a septic system? A septic tank is a tool for proper waste management and disposal; a septic tank is an underground chamber through which domestic wastewater is processed and passed.

The concept is pretty simple- the main tank is buried into the ground and is made water-tight with resilient building material such as fiberglass, concrete, or plastic.

The objective is to separate solids from liquids. When left undisturbed over a certain period, the solids will accumulate at the bottom while the liquids and oil form a layer of grease at the top.

How to construct a small septic system for an RV

It is important to note that having a functional waste management system in the RV is crucial to sustainability.

The basic feature of trailer travel is that one has to be on the move almost always. It means that whichever process of waste disposal you adopt has to fit in with your travel model while also being eco-conscious.

Fortunately, building a small septic system for an RV is relatively easy to work. Several steps are involved to ensure that it works smoothly, but the rest comes easy once you have the logic figured out.

There are few components present in RV, regardless of size or orientation, and act as the anchors of the system.

Gray water tank: This contains the liquids from the sink and the shower. It is not consumable( for obvious reasons) but can be used to wash the RV.

Blackwater tank: The wastewater tank contains liquid refuse from the toilet and all the waste from the shower and sink.

Dumping system: The principle is to hook a sewer hose to the black or gray water tanks and empty them into a dumping facility.

If you wish to DIY a septic system for your RV, keep in mind that you need adequate supplies.

It is also a good idea to invest in good quality products since a functional waste disposal system will not do too well if built out of materials that are not durable.

The idea is to replicate a traditional septic system and account for the obvious difference in scale.

You will need- PVC pipes and elbows, a shovel, pipe glue, a tape measure, paper rosin, and perforated PVC pipes.

You can follow a stepwise procedure to set up the tank.

  • First, locate the main sewer pipe for the RV. Connect a PVC pipe( 5-10 ft) on the plumbing that emanates from the RV. It is the part of the pipe that shall be horizontally fixated and secured by a clamp.
  • Using the tape measure, measure the distance between the bottom of the tank and the inlet hole. Measure also the hole depth from the bottom of the pipe.
  • Next, use a shovel to dig a hole into which you shall place the septic tank.
  • Set the inlet from the rig drain into the tank. Ensure that it is a snug fit. Following this, fill the area around the tank with soil and level it out.
  • Use pipe glue to fix an elbow pipe onto the drain pipe’s end. The elbow pipe should face downwards in the direction of the tank.
  • Dig a ditch near the tank’s outlet, and make sure that the hole is deep enough.
  • Use a PVC pipe to create a channel from the outlet hole to where the trench ends. Attach a PVC elbow to the outlet pipe.
  • Dig another ten-foot hole at the end of the trench. Fill the hole with stones and soil.
  • Attach a perforated PVC pipe at the end of the main PVC. The end of the perforated pipe should be at the center of the stone-filled hole.
  • Put stones over the perforated PVC, ensuring that there are stones around 4 inches over it.
  • Put rosin paper over the stones to avoid the rocks from getting mixed up with the soil and dirt. After the dirt settles, the paper shall dissolve.
  • Once you have placed the tank lid, backfill the trench with dirt.

The points above outline the basic construction of a septic tank. There are, of course, other things to keep in mind.

Always ensure that there is a certain quantity of water in the tank.

The black water tank, for example, requires some prior preparation.

It prevents bad odor and keeps solid waste from sticking to the sides and bottom of the tank.

An additional measure you can take is adding some black water tank chemicals to the water. [Note: If the chemical you are using is available for purchase, you can be carefree that it is also environmentally friendly.] They hasten the process of waste dissolution and largely check odor.

Emptying the black water tank is important to avoid buildup. Remember to dump it out in an appropriate location to avoid improper disposal.

It is always a good idea to empty the black water tank first so that you can use the liquid from the gray water tank to clean out the insides of the former.

Emptying is not enough to preserve an optimal level of health of the septic tank; you must also devise a functional flushing process.

Flushing is a way of eliminating toxins. Investing in a tank rinser is a popular way of performing the same.

If you are looking for more mobility in waste management, a portable black water tank might be a good idea.

It allows one to empty the refuse from the black/gray water tanks via an external tank and markets towards those who favor off-beat paths where sewer connections are scarce.

A portable tank needs to be cleaned and maintained in the same way as a regular tank.

When purchasing tank chemicals, it is best to avoid those with formaldehyde as a component. They can cause lasting damage to the tank material.

After all, prevention is better than cure. Inspect the tanks regularly and keep in hand a cleaning schedule that keeps neglect at bay. You can never go wrong with investing in a heavy-duty water hose to aid in effective cleaning.

Keep stock of RV connectors and couplings, and remember that there may arise a case where you might have to connect two or more hoses to get to the sewer connection.


As I have elucidated in the article, a septic tank system is an essential component of a travel trailer or RV home.

It is imperative for smooth functioning. Therefore, learning how to build and maintain it is a skill you absolutely should know.

The concept, in itself, is simple, and the construction, if followed carefully, should not take too long either.