Pressure Distribution System
A pressure distribution system is a step above a traditional gravity system, designed to provide even wastewater distribution throughout the drainfield. By using a pump and valve box, effluent is pressurized so every part of the drainfield receives the same amount, ensuring proper treatment and long-lasting system performance.
Pressure Distribution at McNair Septic
A pressure distribution system is the second simplest septic system available. This system consists of a septic tank, a pump chamber and a drainfield (AKA leech field). The pump chamber can be incorporated into the septic tank, but is more commonly found in its own second tank. The septic tank must be placed accordingly so that it is downhill from the home/building’s plumbing. A bio-microbial process in the septic tank treats the waste before it reaches the 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: an on/off float (lower) and a high-water alarm float (higher). When the effluent in the pump chamber reaches the on/off float, the pump turns on and doses a set amount of effluent to the drainfield. There, a valve box evenly distributes the effluent between pressurized lateral lines. 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 drainfield is pressurized and all parts receive the same amount of effluent. Each lateral line has orifices 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.
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.
Pressure distribution systems should have an operation and maintenance inspection done every two years of operation, not including the initial inspection to be done the year it is installed. 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 drainfields include parallel, 60-foot-long lateral lines that are spaced six to eight feet on center. More intricately designed drainfields may include lateral lines of varying lengths (from 36 to 60 feet) 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, a valve box lid, and observation port lids at the ends of the lateral lines. 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 Pressure Distribution Systems
What makes a pressure distribution system different from a gravity system?
Unlike a gravity system, a pressure distribution system uses a pump and valve box to pressurize lateral lines, ensuring wastewater is evenly spread throughout the drainfield.
What are the main components of a pressure distribution system?
It includes a septic tank, a pump chamber (often separate from the tank), and a drainfield with pressurized lateral lines that distribute effluent evenly.
How often does a pressure distribution system need inspection?
These systems should have an operation and maintenance inspection every two years, in addition to the initial inspection after installation.
What happens if the system malfunctions?
If the water level in the pump chamber rises too high, a high-water float triggers an alarm, signaling that something is wrong with the system.
How visible is the system after installation?
Only 24-inch riser lids, a valve box lid, and observation port lids will be visible above ground. These are designed to be flush with the ground so they can be mowed over or disguised.
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.
