Pressure Septic System

Septic tanks with gravity flow drainfields have been used for many years in areas not served by public sewers. Unfortunately, not all soil and site conditions are well suited for these conventional systems. To protect public health and water quality, alternative systems are often used in areas where conventional systems cannot assure safe sewage treatment.
A typical pressure distribution system has three working parts:
  • Dosing and resting cycles.
  • Uniform distribution of effluent.
  • Shallow placement of the drainfield.
Pressure System Installation - Stangland septic service in Aberdeen, WA
A typical pressure distribution system has three working parts:
  1. The septic tank.
  2. The pump chamber with the pump.
  3. The drainfield with its replacement area.
Pressure System Installation - Stangland septic service in Aberdeen, WA

The Septic Tank

Septic tank Installation - Pressure System Installation - Stangland septic service in Aberdeen, WA
The typical septic tank is a large buried container made of concrete, fiberglass or polyethylene. Wastewater from your home flows into the tank. Heavy solids settle to the bottom where bacterial action partially decomposes them. Most of the lighter solids, such as fats and grease, rise to the top and form a scum layer.

The wastewater leaving the septic tank is a liquid called effluent. It has been partially treated but still contains disease causing bacteria and other pollutants. From the tank, the effluent flows by gravity to the pump chamber.

The Pump Chamber

Pump Chamber - Pressure System Installation - Stangland septic service in Aberdeen, WA
The pump chamber is a concrete, fiberglass or polyethylene container that collects the septic tank effluent. The chamber contains a pump, pump control floats, and a high-water alarm float. The pump action can be controlled either by the use of control floats or by timer controls. Control floats are set to turn the pump “ON” and “OFF” at levels for pumping a specific volume of effluent per dose. Timer controls are set to produce both the length of the dose and the interval or rest period between doses.

The high water alarm float sounds an alarm to warn you of any pump malfunction. If pump timer controls are used, the alarm also will warn you of excessive water use in the home. The float is set to start when the effluent in the pump chamber rises above the “ON” float. The alarm should consist of a buzzer and an easily visible light. It should be on an electrical circuit separate from the pump.
The pump discharge pipe should have a union and valve for easy removal of the pump. A piece of nylon rope or other noncorrosive material should be attached to the pump for taking the pump in and out of the chamber.

The Drainfield

Drain-Field - Pressure System Installation - Stangland septic service in Aberdeen, WA
The drainfield is a network of pipes placed in gravel-filled trenches (2–3 feet wide) or beds (up to 10 feet wide) in the soil. Effluent is pumped through the pipes in controlled doses to insure uniform distribution throughout the drainfield. The effluent leaves the pipes under low pressure through small diameter holes, and trickles downward through the gravel where it reaches the soil. The soil filters and treats the effluent, removing bacteria and other pollutants before it reaches the groundwater. Every new drainfield is required to have a designated replacement area. It must be protected should that the existing system need an addition or repair.

What if the Alarm Sounds?

If for any reason the effluent level inside the pump chamber reaches the alarm float (faulty pump, floats, circuit, excessive water use, or another problem), the alarm light and buzzer will start. By using water conservatively (avoid baths, showers, and clothes washing), the reserve storage in the pump chamber should allow you enough time to get the problem corrected. To silence the alarm, push the reset light on the alarm panel. Before calling for service or repair, check to see if the problem could be:

  1. A tripped circuit breaker or blown fuse. The pump should have a separate circuit with its own breaker or fuse. If it's on a circuit with other equipment, that equipment can cause the breaker to trip.
  2. A pump or float switch power cord that has come unplugged. If electrical connections are the plug-in type, be sure switch and pump plugs are making good contact in the outlet.
  3. Control floats tangled by other parts in the chamber such as the electric power cord, lifting rope, or pump screen. Be sure floats operate freely in the chamber.
  4. Debris on floats and support cable that is causing the pump to switch off. Lift the floats out of the chamber and clean.

CAUTION: Always turn off the power supply at the circuit breaker and unplug all power cords before handling the pump or floats. Do not enter the pump chamber. Gases inside pump chambers are poisonous and the lack of air can be fatal. If the problem cannot be located with the above steps, call your pump service person or on-site system contractor for service or repair. The service or repair of pumps and other electrical equipment must be done by an experienced person.