Troubleshooting Common Issues with a Mound Septic System in Redmond, WA

Mound septic systems are alternative wastewater management systems typically used when standard sewer systems are unsuitable. Based on the location and soil types present, these systems employ a specially constructed mound-shaped drain field, often installed above the natural surface of the ground. 

Located commonly in Redmond, Washington, and King County, mound systems are critical in managing household wastewater, mainly where traditional septic systems can’t operate effectively.

A mound system works when you build a mound out of sand on top of the soil, and as the sewage flows through the sand, it creates extra treatment for the water. In other words, you have a sand filter.

Like all other systems, mound septics can cause a variety of unpleasant situations. Problems can range from foul odors emanating from toilets to standing water in the yard, pointing towards potential septic issues

Understanding these common issues is essential to maintaining the overall system’s health and performing repairs if required. That’s why today we will focus on the most common ones and also how you can troubleshoot them.

Troubleshooting Common Issues with a Mound Septic System in Redmond, WA

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Signs of Mound System Problems

Recognizing these signs of problems is crucial and can make the difference between minor maintenance jobs and costly repairs

Seeing rapid vegetation growth around your drain field and encountering slow drains, plumbing issues, or foul odors can signal a potential mound system issue. Even signs as subtle as changes in soil texture can indicate a problem.


Look for any unexplained wet or soggy areas around the mound system. Seepage may indicate a problem with the drainage or the absorption capacity of the soil, which can lead to system failure.

Abnormal Vegetation

Notice changes in the vegetation around the mound system and the drain field. Overly lush or dying vegetation may signal issues with the soil’s ability to absorb and treat wastewater properly.

Septic Alarms

Modern mound systems are equipped with special septic alarms. If you hear an alarm or notice warning lights, it could indicate a problem like high water levels or pump failure. Prompt attention is crucial to prevent system malfunction.

Foul Odors

Unpleasant smells around the mound area may suggest a problem with the system’s wastewater treatment functions. Foul odors can indicate improper decomposition of waste, and addressing this promptly is essential.

Soggy Ground Surface

Excessively soggy ground around the mound may indicate a malfunction, especially during dry periods. It could be due to a blockage, overloading, or issues with the distribution of treated wastewater.

Reasons That May Cause Mound System Issues

Sand Erosion

When the sand erodes, it exposes the drainfield pipe, leading to the emergence of sewage on the surface. It occurs due to the erosion, and the effluent becomes exposed.

Mound Clogging

If the mound becomes clogged, it renders the sand impervious, preventing water from percolating through the sand and soil. Consequently, water may rise to the surface instead of being absorbed into the sand.

Accumulation in the Drainfield

The mound system’s drainfield can become clogged due to the accumulation of sludge and debris. This internal clogging hinders the proper flow of wastewater through the drainfield.

Biomat-Induced Sand Clogging

The biomat, which is crucial for wastewater treatment, can cause clogging in the sand. Although the biomat is essential, excessive thickness or impermeability can lead to poor drainage. This results in reduced absorption of treated wastewater into the soil, exacerbating mound system issues in Redmond, WA

Mound System Regular Maintenance

As a homeowner or a business owner in Redmond, WA, you need to have your mound septic properly maintained.

Proper care of such OSSF involves several main things: 

  • Know your territory – Before you get green-thumbed with a garden, build a fancy shed, or cool off with a pool, ensure you’re in the clear regarding your on-site sewage facility. Know exactly where your system and the replacement area are situated. 
  • Be mindful of water usage – Make it a habit to conserve water and spread your use throughout the week to not overburden the system. Remember, the more wastewater you create, the more work your mound has to do.
  • Aim water away from the mound – Surfaces like roofs, driveways, or patios can channel much water. Ensure this water goes somewhere other than your mound and replacement area. Keep structures, ditches, and driveways at a safe distance to let your mound drain properly.
  • Traffic control Keep heavy vehicles, equipment, or animals away from the mound and replacement area. The added weight can damage your pipes.
  • Maintain appearances – How you landscape your mound matters. Avoid capping it with impermeable materials like concrete or plastic, which restrict air supply and reduce evaporation – both crucial elements for efficient wastewater processing. Grass turns out to be the best attire for your mound.
  • Conduct regular inspections – Look for red flags like odors, wet patches, or surfacing sewage. If you find the liquid level in your system’s inspection pipes continually hovering above 6 inches, that could spell trouble. Reach out to your local Environmental Health Department for a hand.  

Now, that might seem a fair bit. But trust us, these small measures go a long way in maintaining your mound septic system.

Getting Professional Help

Regular professional maintenance is critical to the high performance of your mound septic system. King County and Redmond, Washington’s Environmental Departments guidelines mandate conducting an annual inspection. 

Whether routine pumping or installing a new tank, selecting a professional contractor is essential. Septic companies ensure businesses and city homes have efficiently operating septic systems through regular pumping, which consequently prevents costly replacements.

Fresh N Clean Septic provides top-notch septic services, ensuring that you get the best maintenance and repair job on your Redmond mound system.

Act Now and Fix Your Septic Problems

Wrapping up and addressing common issues with your mound septic system is vital if you want to avoid costly repairs and prevent environmental hazards. Understanding the signs of potential problems and the value of regular maintenance and professional services cannot be understated.  

Next time you notice an issue, don’t hesitate to contact a professional from an experienced septic company in Redmond, like Fresh N Clean Septic. We are well-versed in inspecting, maintaining, servicing, and repairing mound septic systems, serving King County and beyond. 

Troubleshooting Common Issues with a Mound Septic System in Redmond, WA

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Frequently Asked Questions

Are there specific maintenance tasks to prevent mound clogging?

Yes, they include regular inspections and septic tank pumping, proper wastewater disposal practices, and avoiding activities that can harm the mound are essential preventive measures.

Can a mound septic system be installed anywhere?

Mound septic systems are particularly suitable for areas where traditional systems may not be feasible.

Are mound systems environmentally friendly?

Mound systems are environmentally friendly due to their effective waste treatment processes, resulting in minimal environmental impact.