What Can Cause a Septic Tank to Back Up?

What Causes a Septic Tank to Back Up With Your Home System?

Let’s take a look at a topic that may cause chills to run up and down your spine…and with good reason!

What would cause a septic tank to back up?

The answers to that one seemingly simple, innocent question are as many and varied as the people who use the facilities emptying into the septic tanks! Let’s look at a few of them together.

Answer #1.

A septic tank backs up because it’s tired of going forwards.

Haha. Gotcha on that one, right?

Ok, so I couldn’t resist one very corny joke.

More serious now:

One of the first things to determine is whether the backup is actually the Septic Tank itself, or whether it may be a clog in the plumbing lines somewhere…

Sometimes customers who experience a backup will call in to have their septic tank pumped, and once our technicians pump the septic tank, the backup is still just as backed up as ever! The reason is often a clogged plumbing line rather than an actual backed-up septic tank. Some common causes for clogged plumbing/drainage lines leading to the septic tank are as follows:

Tree Roots

This is one of the most common plagues of drainage lines everywhere…we love those lovely lawns shaded by a giant, stately old oak or maple trees, right? They’re so beautiful. While it’s true that the upper part, easily seen and appreciated, is beautiful, these trees have a sinister counterpart underground….the wicked root system which is always in search of…water! Tree roots have an uncanny ability to smell water from far away and will go to great lengths to penetrate whatever stands between them and the precious water they so badly need for survival. If a tree root finds the tiniest of cracks in a drainage pipe, it will send a tiny thread, a hair-thin root, in through that crack to begin sucking up that water and sending it up to the tree.

Once inside, two things begin to happen simultaneously. The tiny root inside immediately sends out more threadlike roots inside the pipe which begin growing instantly. These roots grow and multiply inside the pipe, sucking up the nutrient-rich water and sending it back to the tree. At the same time, as these roots grow, the tiny root going through the tiny crack in the pipe also grows. As tiny as it is, it has tremendous strength. It will eventually burst the pipe completely, causing a rupture in the line, which can bring further complications.

Minor root infestations can be treated by a high-powered water-jetting machine, and/or a mechanical augering cutter tool. Once the roots have been cut out and removed, they should be treated with a root killing chemical to prevent or delay reinfestation. Major infestations will have to be repaired by digging up the infested pipe, removing and replacing it with a new pipe. Special care needs to be given to the connection points in these repairs, as the slightest crack will result in a repeat of the original problem in time.

Other common system damage causes include:


Do. Not. Ever. Pour grease down your sink. Period.

This is one of the surest ways to bring about a backup of your plumbing lines and your septic tank.

Grease will coagulate once it comes in contact with water. It will then harden into a firm substance inside your pipe, and eventually clog your pipes completely, resulting in overflowing toilets, sinks, and showers…have I said enough?

A few other things you might not think of right away…

Don’t try to flush your false teeth…they have a nasty habit of causing backups.

Don’t flush your sunglasses either…same reason.

Don’t flush baby wipes.

Don’t flush sanitary napkins or feminine products.

No condoms.

Don’t flush bleach, or use excessive quantities of antibacterial soaps or cleaners…they will kill the living bacteria that make your septic tank work properly.

Any or all of these will work together to form the perfect backup recipe.

And yes, we have seen all of these terrifying scenarios….and many more.

Improper plumbing installations

Sometimes a do-it-yourselfer or a novice plumber may install piping with insufficient fall, or drop, in the piping. This causes the water in a flush to run too slowly, permitting the solids to settle to the bottom of the pipe as the water seeps away. By the time the next flush comes along, these solids have dried out and attached to the bottom of the pipe, and buildup begins to occur, finally leading to a clog, and causing a backup.

Another cause of backups:

Effluent filters on the outlet of your system.

These are designed to protect your leach field from overload, preventing costly repairs of your septic system. Their function is to keep all solids within the septic tank and allow only water to go out to the leach field.

These filters require regular cleaning and maintenance to ensure their proper functioning. Failure to clean and maintain your effluent filter will eventually cause….yep you guessed it…backup!

One final common cause for Septic damage:

Excessive rain or flooding

Especially in situations where groundwater and surface water are not properly diverted and drained away from your septic tank and leach field, heavy rains or prolonged wet or rainy seasons often result in backups in your septic system. The long-term cure for this is to have proper drainage work done to ensure that your septic system is kept protected from stormwater. For all these problems and many more, give us a call at Shankster Bros. to find solutions!