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How To Tell If Your Septic Tank Is Full (7 Warning Signs)

signs of a full septic tank

How To Tell If Your Septic Tank Is Full

When it comes to home maintenance, some things are easy to know when to take care of. For example, smoke detectors.  You know that you should change the batteries and clean off the dust at least once per year.

But what about things that aren’t so easy to know when to service, like your septic tank.  How are you supposed to know when your septic tank is full? The tank is underground, so out of sight, out of mind, right?

Well here are some of the most common signs of a full septic tank.

Warning Signs Of A Full Septic Tank

The most common warning signs of a full septic tank are: 

  • Slow Drains
  • Sewage Backup
  • Pooling Water
  • Abnormally Green Grass
  • Bad Odor Outside Or In The House
  • High Nitrate Content in Well Water

Slow Drains

One of the easiest clues that your septic tank might be full is when the water in your drains begins to go down slowly.  Perhaps the bathtub takes forever to drain or the kitchen sink doesn’t drain nearly as fast as it used to.

Your first thought might be that the pipes are clogged. But chances are, if more than one drain is not draining at a normal rate, then it’s probably a sign that your septic tank is full.

If this is happening, now would be a good time to call a septic tank service near you to come and investigate the issue.  In these situations, your septic tank has been very nice to you in giving you this relatively benign warning sign.

Sewage Backup

Not every full septic tank is nice enough to give you the warning of slow or sluggish drains.  More times than not, the sewage will just begin to back up into the house when the septic tank is full.

This particular sign of a full septic tank can be astronomically expensive as a homeowner. So please do not ignore other, more benign signs of a full septic tank.

Believe me when I tell you, from experience, you do not want raw sewage backing up into your house. Ask my wife. She’ll tell you all about it.

Pooling Water

If there are areas of pooling water in your lawn where you think your septic tank is located, then that’s a tell tale sign that your septic tank is full and needs to be emptied. The reason there’s water pooling up onto the surface is because when septic tanks fill, the solid waste can occlude the outlet pipe that leads to the septic system’s drainfield. When this happens, and the septic system begins to overflow, the sewage has no place to go other than up! It’s time to call and have it emptied.

Abnormally Green Grass

When your septic tank is functioning normally, you should not be able to tell a difference in the color or health of the grass that’s over the top of the septic tank, generally speaking.

However, if the grass in a specific area of your yard starts to take on a much more lush green appearance, and you haven’t been fertilizing and taking extra special care of just that one area, then that’s a great sign of a full septic tank.

What’s happening is the same thing as above. The septic tank is full and the water has nowhere to go except to the surface. But the rate of seepage may be slow enough that it’s not yet pooling on the surface. But instead, is seeping just enough to provide some serious homemade fertilizer to your grass.

Bad Odor Outside Or In The House

Are you starting to catch a funky whiff of something when you walk outside your house or even worse, inside your house? If so, then that’s a pretty good sign that your septic tank is full. Time to call and have it inspected.

What happens is as the septic tank begins to reach capacity, the gasses inside the septic tank become trapped and have nowhere to go.  Much like the water inside a full septic tank, the gasses have nowhere to go but up and out. And that might be up through the ground or even back up through the pipes and into the house.

As gross as this may sound, you should take it as a gift from your septic tank as a warning sign.  It’s much easier and less expensive to deal with bad smells than it is to clean up backed up sewage.

High Nitrate Content in Well Water

In addition to having a septic system at my house, I also have a well.  So this sign of a full septic tank only applies to you if you have a similar setup. If you don’t have a well, then you can disregard this one.

It’s best practice to have your well water tested at least once a year. During this test, if you find that higher than normal nitrate levels are in the well water, then you might want to consider those nitrates are coming from a full septic tank.  Nitrates find their way into the well water as a result of an overflowing septic tank. That septic water then leaks into the well water increasing nitrate levels.

Importance of Maintaining A Regular Septic Schedule

The best thing we as homeowners can do to know when a septic tank is full is to keep a regular maintenance schedule for our septic tank.  I realize this can be difficult to do, especially since the entire septic system is out of site. I know for me that means out of mind!

Depending on how many people are living in your house, or are tied to the septic tank, will determine how often you should empty your septic tank. Generally speaking, you should assume your septic tank is full and have it emptied once every 3 to 5 years; more if its heavily used.

Final Thoughts

Ignoring the signs of a full septic tank can not only be disgusting, but can also be very expensive.  Don’t ignore the signs. Even if you just suspect that your septic tank is full, call your local septic service company and have them take a look.  Compared to the costs of emptying the tank compared to the costs of repairing or replacing a tank can’t even be compared.

Do you know of other helpful signs of a full septic tank? If so, leave a quick message below and share your knowledge.

Related Posts:

1. How Long Does A Septic Tank Last (Get The Most Out Of Your Tank)

2. The Best Toilet Paper For Septic Tanks (Top 3)

3. Does Shower Water Go Into The Septic Tank?


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