Subsurface Drip Septic System
A subsurface drip septic system is an advanced solution that uses drip lines instead of traditional lateral lines, allowing wastewater to be filtered into the soil at a steady, controlled rate. This prevents the drainfield from being overwhelmed and ensures clean, safe treatment before reaching the water table.
Subsurface Drip at McNair Septic
A subsurface drip system is like an aerobic system, but it uses drip lines instead of lateral lines so that the soil under the drainfield is not overwhelmed. This system consists of a trash/dose combo tank, an aerobic treatment tank, and a drip drainfield. The tanks must be placed accordingly so that they are downhill from the home/building’s plumbing. Waste enters one of two separate compartments in the trash/dose tank. As the compartment fills, waste flows through the outlet to the aerobic treatment tank. Here, an aeration pump constantly pumps air into the effluent to speed up the bio-microbial treatment process. Then the effluent is transported back to the trash/dose tank, where it enters the second chamber (pump chamber). Further settling occurs in the pump chamber, ensuring that the pump does not send solid material to the drainfield.
The pump chamber contains two floats: a low level/off float (lower) and a high-water alarm float (higher). Time dosing is set upon installation. The system will turn the pump on a set number of times each day for a set amount of time. If the system pumps too much effluent out of the pump chamber, the low level/off float will turn the pump off automatically until its next dose time. If the effluent level in the pump chamber rises too high between doses, the high-water alarm float will trigger an alarm which indicates that something is wrong with the system or that dose times need to be adjusted to occur more frequently.
After leaving the pump chamber, a valve box evenly distributes the effluent between pressurized drip line loops. The system must use a pump even if gravity flow can be achieved from the pump chamber to the drainfield. This is to ensure that the drip lines are pressurized and all parts receive the same amount of effluent. Each drip line has emitters that allow the effluent to reach the soil throughout the entire drainfield at the same rate. The effluent then filters through the soil and is clean by the time it reaches the water table.
Not all effluent pumped to the drainfield escapes through the emitters. Effluent that circulates through the loops without dripping into the soil is returned through return pipes to the pump chamber where it will be pumped back through the drip lines until it does drip into the soil.
If the water level in the pump chamber ever reaches the high-water alarm float, the alarm will go off, indicating that there is something wrong with the system.
Subsurface drip systems should have an operation and maintenance inspection done once every year of operation. Concurring reports may need to be turned in to the county.
Septic systems are sized according to the amount of waste they will be treating, usually estimated by the number of bedrooms in the home. For non-residential buildings, water usage usually determines the size.
The most basic drip drainfields include parallel drip line loops that are spaced two feet on center. More intricately designed drainfields may include drip lines of varying lengths that branch out from the valve box in multiple directions.
Upon installation, the only parts of the system that will be visible from above ground are 24-inch riser lids above the tanks, access ports above the tanks and a valve box lid. Each of these lids will be flush with the final grade and can be walked on, mowed over or disguised to lessen
noticeability.
Drainfields should be treated as fragile to increase their longevity. Large animals such as cows or horses should not be kept on drainfields and vehicles should not be driven over them. Vegetation with intrusive roots should not be planted near them. Finally, a home owner should be mindful of what is going into the system.
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FAQs About Subsurface Drip Septic Systems
How does a subsurface drip septic system work?
A subsurface drip system uses a trash/dose tank, an aerobic treatment tank, and a drip drainfield. Wastewater is aerated for treatment, then distributed evenly through pressurized drip line loops with emitters that slowly release effluent into the soil.
Why would I choose subsurface drip over other systems?
Subsurface drip systems are ideal for properties with shallow soils, small lots, or areas where traditional drainfields could fail. The drip lines prevent overloading by dispersing wastewater more gradually and efficiently.
How often does a subsurface drip system need inspection?
These systems should have an operation and maintenance inspection once every year. Depending on county regulations, reports may need to be submitted as part of ongoing compliance.
What does the system look like once installed?
After installation, the only visible parts are the riser lids above the tanks, access ports, and a valve box lid. These are designed to sit flush with the ground and can be walked on, mowed over, or disguised in landscaping.
How can I protect my subsurface drip system?
To extend the life of the system, avoid driving vehicles, keeping large animals, or planting deep-rooted vegetation over the drainfield. Also, be mindful of household waste that enters the system.
The Process
Planning
All we need is your parcel number or address to begin. We research your property in advance, gather details about your future plans, and may schedule a site visit or call. Any questions are addressed quickly to keep the process moving.
Soils Evaluation
Most projects start with a soil evaluation (perc test), the first step toward system approval. We handle everything—from digging and testing to county applications, fees, and paperwork—while keeping you updated every step of the way.
On-Site Septic System Design
After completing the soil evaluation, we quickly create a detailed, cost-effective septic design, typically within one to two weeks, that includes all calculations, maps, and specifications, while handling every detail of the submittal process for you.
Review and Permitting
Most counties allow up to three weeks to review septic designs and soil evaluations, though some return them sooner. Once approved, we’ll send you a copy and can also forward it to licensed installers so you can receive system bids.
Taking Care of You
We handle everything—even the required county as-built map—so your septic system is approved and recorded. With no complex contracts, we start right away and keep things moving. Consultations are always free, so call us anytime.
Support
We can assist you in finding reputable septic installation and maintenance companies that can service and maintain your new system.
