Mound System in Portland Area

Portland / Vancouver Metro - The Dalles - Hermiston OR & Tri Cities WA

Not every property can support a traditional drainfield. The alternative is a mound septic system that uses a large mass of soil to treat sewage. These systems suit locations with shallow bedrock, a high water table, or limited soil depth. To prevent backups, they also need proper installation and routine checks to guarantee proper drainage. Speedy Septic has been providing mound system services to Oregon and Southwest Washington homeowners for over 40 years. Learn more about these systems and our comprehensive septic mound system processes.

What Is a Mound Septic System?

A mound system is a type of drainfield built above the natural soil surface, rather than below, as a traditional system is. It uses sand fill material, a gravel bed, and a chain of small pressurized pipes. Mound septic systems consist of three main components:

• The septic tank.
• The dosing pump chamber and pump.
• The mound and replacement area.

Mound systems are different from conventional gravity systems.

How Does a Mound Septic System Work?

A mound septic system works in three steps:

• Step one: Wastewater flows by gravity from the septic tank to the dosing pump chamber.
• Step two: Once the wastewater reaches the dosing chamber, it’s distributed into a network of pipes.
• Step three: The wastewater moves through the pipes and trickles into the soil or sand mound for treatment.

Septic Tank and Wastewater Separation

Everything begins in the septic tank. Wastewater from your home flows into the tank, where heavy solids sink to the bottom and lighter fats, oils, and grease float to the top. The anaerobic bacteria in a septic tank begin breaking down the organic waste.

Next, the middle layer, called effluent, flows out of the tank into the pump chamber for distribution. Pump septic tanks regularly to prevent solids from reaching the pump chamber and damaging your mound system.

Pump Chamber and Pressure Distribution

Effluent collects in the chamber, and a float switch triggers the pump to distribute it through pipes resting in the mound. This pressure distribution prevents overloading one area and gives the sand and soil mound time to rest and absorb air between cleaning cycles.

Sand Filtration and Soil Treatment

Once the effluent flows out of the pipes into the mound, the sand and soil clean it organically and physically. Beneficial bacteria in the sand continue to break down the waste, while the sand filters out larger particles. Once the water reaches the native soil underneath, it is substantially cleaner and disperses into the area’s groundwater.

When Is a Mound System Required for a Property?

A site evaluation and soil test will determine whether a septic tank mound system is needed. A mound system is needed if:

• The home has thin soil or dense clay that won’t absorb and treat effluent properly.
• The home’s soil is extremely coarse and drains too quickly.
• The home’s water table is high, and the wastewater needs extra separation and treatment.
• The area has sloped terrain, limited usable space, or is prone to flooding.

Common Mound Septic System Problems and Warning Signs

Mound-type septic systems have more components than a typical drainage field, which means more can go wrong. Look out for these warning signs that your mound system is failing:

• Sewage odors near the tank, mound, or pump chamber.
• Slow drains or gurgling sounds, which can mean a full tank or a blockage.
• A pump alarm sounding off, indicating high water levels or pump failure.
• Unusually lush green grass over the mound or your surrounding lawn, which can mean effluent leaks.
• Sewage backups in your house.
• Wet or spongy surface on or around the mound.

Mound System Maintenance: How Often Does It Need Service?

To avoid backups, pump alarms, and genuinely messy situations, Speedy Septic recommends a mound system inspection at least once a year.

This maintenance check ensures the pumps, floats, and pipes are in good working order and that effluent filters are professionally cleaned.

Most septic tanks also require pumping every three to five years. Always avoid flushing non-flushable wipes and pouring grease down drains to prevent clogs.

What Happens During a Professional Mound System Service Visit?

At Speedy Septic, we always follow a diagnostic process for every mound system service job.

• Step one: We begin with a septic tank inspection, measuring the sludge and scum levels, and clearing any solids.
• Step two: We clean the effluent filter.
• Step three: We move to the pump chamber and inspect the floats and alarm system.
• Step four: We check the distribution pipes and make sure the effluent isn’t piling up in one line.
• Step five: We look for any odors, wet spots, or breakouts in the mound.

If we encounter any issues with your residential mound septic system, we let you know right away and offer our professional recommendation.

Why Homeowners Choose Speedy Septic

Homeowners in Oregon and Southwest Washington continue to choose Speedy Septic for the following reasons:

• We offer pumping, repairs, maintenance, and installation services.
• We turn septic pumping material into fertilizer for local farms.
• As our name suggests, we pride ourselves on being an extremely fast septic service provider.
• In addition to mound systems, we offer drainfield repair and installation.
• We offer 24/7 customer service.

Mound Septic System Services in Oregon and Southwest Washington

We are proud to offer mound and conventional septic system services to:

• Portland and surrounding metro communities.
• Vancouver, WA area.
• Eagle Creek and Clackamas County.
• The Dalles and Columbia Gorge.
• Hermiston and the Tri-Cities service region.

Schedule Mound Septic System Service with Speedy

If you’re worried your mound septic system is failing, or it’s been a while since its last inspection, knowing who to call can save you the stress of a messy situation. Speedy Septic will arrive quickly to assess your system and provide fast repairs, pumping, and maintenance services. Call us today for a consultation.

Frequently Asked Questions

How much does a mound septic system cost?

Septic mound system costs vary widely, depending on site specifications, ground access, size requirements, and permit regulations. When buying a property, always have your soil inspected to see if the cost of a sand mound septic system works with your budget.

How long does a mound septic system last?

Generally, a mound septic system lasts 20 to 25 years. With diligent maintenance, including regular pumping and inspections, these systems can last longer.

Can a failing mound septic system be repaired?

It really depends on what is failing. A leaking tank may need patching or replacement, and distribution pipes can also be repaired. Speedy Septic will always assess each situation.

Can you plant grass or landscape over a mound septic system?

You can plant grass and shallow-rooted plants over a mound septic system. Always avoid edible plants and any large trees, as these roots can disrupt the mound.

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