How Does A Septic Leach Field Work?

Last Updated On June 11, 2024

Updated on September 14, 2022



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How Does a Septic Leach Field Work

We might wonder how the septic leach field works if our home has a septic system. 

A leach field consists of multiple perforated pipes that lay in parallel trenches in our yard. These pipes run at a downward angle away from our septic tank. They are then backfilled with gravel and sand before the original soil is put back on top of the trenches. 

As the overflow from our septic tank runs into the leach field, it pours evenly down each trench. The holes in the perforated pipe allow the liquid to filter naturally into the gravel and sand, removing any chemical or bacterial by-product from the wastewater as it settles down through the soil.  

The leach field will be in a large open area of our yard. We must keep any unnecessary weight off our leach fields. The soil composition will need to meet local “perc” standards, as well.

A septic leach field works as a drain and requires negative air pressure to function. Pouring a concrete pad or installing any foundation over our leach field can starve the system of oxygen. 

A failing absorption field can result in all of our typical plumbing problems. From slow drains to toilets that don’t flush properly, leach fields that can’t drain properly can affect our entire septic system. 

What's In This Guide?

      What’s The Difference Between A Drain Field And A Leach Field?

      A common question among septic tank owners is, “what’s the difference between a drain field in a leach field?” The truth is, a leach field is a drain field. They are the same thing. 

      Because of the way the leach lines work and how the water drains from our septic tank, some people just call it a drain field. 

      The leech field can go by many different names. Depending on where we live, the drainfield could also be called a filter bed, a leaching bed, or even a percolation bed. 

      How Do A Septic Tank And Leach Field Work Together?

      All septic tank systems consist of three parts; the septic tank, the sewer pipes, and the leach field.  Our waste flows down the sewer pipes.

      How do a leach field & septic system work together? When waste goes down our drains, it flows down a series of plumbing pipes, eventually dropping into our septic tank. The solids stay at the bottom and start to decompose. 

      As long as our septic tank is maintained, the solids will turn into sludge. The decomposition process will never stop. 

      As the tank fills to the top with wastewater, the liquid flows into the leach field in our yard. The water absorbs through the gravel and sand through the holes in the perforated leach lines. 

      A clogged drain or vent can create plumbing issues in your home, and so can a blocked leach line. Repairing a leech line or the entire leach field can be extremely expensive. If a drainfield is maintained, it should last about 25 years without any issues. 

      Did you know?  Our septic system works in two parts. The septic tank breaks down the solids. The leach field takes care of the liquids. 

      did you know How Does a Septic Leach Field Work

      Maintaining & Troubleshooting Your Drain Field

      Many people don’t know about septic leach fields because they are typically silent and invisible. As homeowners, we hope they stay that way!

      We need to keep our leach fields maintained. This ensures that our septic drain field will continue to function. 

      When the drainfield needs attention, we will most likely see it, hear it, or smell it. We may even hear the sound of gurgling pipes and bubbling or toilets. We may see backed-up toilets or slow-running drains

      The smell of sewer gas or puddles of water at the ground surface signal when our septic leach field needs attention. We must maintain and troubleshoot our drain field before any issues arise. This can saves us a fortune in repairs later.

      Identify where to find the lid of your septic tank, and check levels at least once per year.

      How Can I Maintain My Septic Leach Field?

      As a homeowner, you may be thinking, “how can I maintain my septic leach field?” The best way to maintain what seeps into our leech lines is to control what goes down our drains. 

      The most important rule of having a septic system is only flushing items that can decompose organic material. This includes using the right toilet paper for your septic tank and keeping certain foods out of the sink drain. 

      We may have some control over the solids that go down our drains, but how can we limit the amount of liquid we use daily? 

      Doing fewer loads in our dishwashers and washing machines is a great start. It’s also a good idea to only run them when they are full.  Fewer fluids running down our drains “all at once” is an obvious way to limit the water that builds up in our leach field. 

      We should try limiting the amount of water that runs into that part of the yard. From our property’s water retention to the rain gutters on our roof, it’s crucial to keep as much water diverted from our leach field as possible. 

      We also need to check and maintain the septic tank distribution box regularly. 

      The septic leach field is part of the entire septic system so pumping the septic tank itself is a big part of maintaining the septic leach field. Use enzymatic and probiotic treatment products to maintain a healthy bacterial balance, especially if you use chemical-based cleaning products in the house.

      If any issues arise in the leach lines, we may need to add a leach field treatment. A chemical compound can is used to unclog and clear any blocked holes in our Leach pipes. 

      Here is a video showing how septic leach line treatments work. 

      We use and highly recommend this product discussed in the video. It works, and you can find it here.

      What Are The Signs Of A Failing Leach Field?

      We may know how to maintain a septic drain field. It’s crucial to know the signs of a failing leach field. 

      Standing water or sinking soil at our leach field is a good sign that the leach lines are blocked. If enough time passes, we also might see greener grass and taller plant life around our leech field and septic tank. 

      Most plumbing issues in our home can result from damaged or blocked leach lines. Slow drains, toilet backups, and a sewer smell from the drain can all be signs of failing leach lines. 

      Leach lines are the primary source of most septic system issues. Maintaining our septic tank and leech field is crucial to saving time and money in the future. 

      A typical leach field will last twenty-five years to fifty years if maintained properly. If an emergency blockage happens somewhere in our drain field, it may require additional leach field treatment. 

      Just like unclogging the drains inside our home, we pour this liquid into the distribution box of our septic system. The leach field treatment is evenly dispersed down each leach line freeing up any debris and clearing out all the perforated pipe holes in the leach lines.

      How Long Does It Take For A Leach Field Treatment To Work?

      The typical leach field treatment is a chemical or enzymatic compound manufactured to break down solid waste. It doesn’t take long for the enzymes to start working. 

      As long as the conditions are right inside our septic tank, the solids will begin to break down within two to four hours. In around 48 hours, we should notice a faster flow in our sewer lines. If the issue persists, we can try another treatment.

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      About Plumbing Navigator

      We write about "all things plumbing," helping you navigate common questions, repairs, and the best plumbing products on the market.

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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