Despite their seeming simplicity, drainfields are critical parts of any home septic system. A properly functioning drainfield must absorb and drain wastewater (effluent) rapidly enough to avoid contaminating or inundating the surrounding soil. Drainfields often fail when they can no longer provide adequate drainage due to compaction, contamination, or changing soil conditions.

Unfortunately, replacing a drainfield can be a costly endeavor. This process requires significant excavation, and it will usually involve rerouting plumbing from the septic tank. Restoration is usually a better option, but how do you know which restoration option will be the most cost-effective option for your drainfield?

Understanding Drainfield Failures

There's no single reason why drainfields fail, and a single drainfield may have multiple points of failure. If you're planning to restore your drainfield, it's crucial first to understand why it failed and whether the conditions that created that failure still exist. To answer these questions, you'll need a plumber with septic system experience to inspect and test your existing drainfield.

In general, there are four common reasons that drainfields fail:

  • Physical damage, often caused by vehicles driving over the field
  • Compaction due to natural causes such as soil settling, flooding, etc.
  • Bacterial balance issues, often due to improper septic system maintenance
  • Saturation due to system overuse or overloading

It's important to understand which issue or issues your drainfield has to determine if it's a good candidate for restoration and, if so, the best way to approach the problem.

Forming a Plan of Action

Once your plumber determines why your septic drainfield failed, they should be able to suggest a few options to restore it without installing an entirely new field. Sometimes, the answer may be as simple as expanding or upgrading the drainfield. This solution may be effective if your system is too small for your current household size, although you may also need to upgrade your septic tank capacity.

More complex failures will often require more complex solutions. Aeration is often the go-to approach if your field fails a percolation test. Aeration uses specialized equipment to loosen and aerate the soil, restoring its ability to drain effluent safely. Aeration may not be an option for heavily compacted soil, but it's often an effective approach for less severe cases.

Finally, it may be necessary to address problems caused by improper maintenance. For example, an overloaded septic tank can allow solids to enter the drainfield, creating clogs and allowing anaerobic bacterial mats to form. Even if your drainfield requires additional remediation, it will also be necessary to resolve these issues and resume a proper maintenance schedule to avoid them in the future.

Contact a professional to learn more about drainfield restoration