DIY Septic Tank Inspection

A septic tank cover in the ground.
What You'll Need

A common misconception is that if you haven’t needed to pump your septic tank in so-many years, it’s working properly. Unfortunately, many people avoid checking their septic tanks until it’s too late. Septic tanks often need inspections, even when there are no signs of a problem. Some experts recommend an annual inspection, while others suggest inspections every 3-5 years. You can save money on these frequent check-ups if you learn to do them yourself.

The Differences Between One-Compartment and Two-Compartment Tanks

Septic tanks.

There are several parts to a septic tank and knowing them can make your job of inspecting a lot easier. To start, you need to know if you have a one-compartment tank or a two-compartment tank.

A one-compartment tank can hold 500-1,000 gallons. These are older systems that were installed before 1976. Just like it sounds, the sewage all goes into the one tank. There is typically one manhole in the middle of the tank.

In a two-compartment tank, you have two manholes—one for each side. It can hold between 1,125 and 1,200 gallons. The sewage from your house goes into a pipe that is t-shaped. From there, it separates into layers in the tank. The lighter liquids like grease form a layer, called scum, on the top. Heavier things settle to the bottom and are broken down by bacteria into sludge or gasses. The second compartment is typically filtered more than the first.

Problems often occur when one of the levels of scum or sludge reaches the ends of the t-shaped pipes and clogs them up.

Step-by-Step Inspection

A septic tank cover and tools on the ground.

Based on the following tests, you should be able to determine if you need to have your septic tank pumped to keep it from clogging.

WARNING: You need to be cautious when inspecting the tank yourself. The fumes from your tank could cause you to pass out and falling in the tank would be extremely dangerous and even fatal.

Step 1 - Begin by Finding Your Tank

If your tank has risers or you have a diagram of where the tank is, it will be much easier to find. If not, you will need to get a long pipe to poke holes in the ground to follow the main pipe all the way from your house to the tank. Be careful not to poke your pipe too hard or else it can damage the sewage system. The tank will most likely be one to three feet underground and five or more feet from your home.

Step 2 - Remove the Covers

Put on some gloves to keep your hands protected from all the germs hiding in your septic tank. Then, you will need to remove the manhole covers before you can do any inspecting. This gives you access to the tank.

Step 3 - Make a Measurement Tool

Find something around your house that you can use to gauge distance. Measure out notches on a long pole, so you can see the distance between the layers in your tank. You can use a long pole or connect two pieces, like a garden hoe and another wooden pole. You just need to make sure the tool you use is long enough to reach the bottom of your tank.

Step 4 - Check Your Inlet Chamber

Lower your instrument into the tank until you feel some resistance. When you hit the resistance, pull the measuring tool back out and get a read on the height of the scum. Then, insert your tool once again to find the bottom of your inlet pipe. If the two measurements are within three inches, you need to pump your septic tank.

Then, check the sludge. Push your measurement tool to the top of the sludge. Mark the stick ground level. Then find the bottom of the outlet pipe and take another measurement. If the numbers are 12 inches apart or less, it’s time to pump.

Step 5 - Check Your Outlet Chamber

A lot of scum in the outlet chamber could signal a problem with your tank. There shouldn’t be much scum in this side at all.