Frequently Asked Questions about your sewage system and lift station

  • How does a lift station work?

A typical lift station consists of 6 major components, Wet Well, Dry Well, Pumps, Valves, Float Switches, and Electrical Controls.

control panelThe Electrical Controls are contained in an above ground Control Panel.

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  The Dry Well contains shut off valves and check valves which prevent water from flowing back into the station from the main sewer system.

 

 

 

 

 

 

 

 

typical lift station

 

The Wet Well contains the Pumps which sit at the bottom of well and Float Switches which are suspended at different heights in the well.

There are typically 4 Float switches in a Lift Station; the Off Float, Lead Float, Lag Float, and Alarm Float. The Float that is suspended lowest in the station is the Off Float. This Float should be suspended at a height just above the top of the pumps. The Lead Float is suspended above the Off Float, the Lag Float above the Lead Float, and the Alarm Float above the Lag Float.

As water enters the Lift Station and the level rises in the Wet Well, the lead Float Switch tips sending a signal to the Control Panel which activates the first Pump. Should the level continue to rise due to high flow or poor pump performance the lag Float Switch tips; sending a signal to the Control Panel to activate the second Pump. At this point one of two things will happen. If the station is performing properly, the level of the water in the Wet Well will drop to the Off Float which signals the control panel to turn off both pumps. If the station is malfunctioning and the level continues to rise; the Alarm Float will tip which activates an audible and visual alarm. This allows the necessary personnel to be notified so that the station can be inspected and repaired as needed.

 

 

 

 

 

  • Why do I need my lift station maintained monthly?

To prevent overflows and emergency situations and assure that your equipment is operating correctly and at maximum efficiency at all times.

  • How can I prevent lift station breakdown?

Don’t flush anything down the toilets other than human waste and toilet paper.

Never pour cooking grease down any drain. Let grease cool and dispose in the garbage.

  • How often do I need to have my lift station cleaned?

This depends on the size of your wet well and what is flushed down the drains. Cooking grease is the most common cause of lift station failure; however, solids can build up in the bottom of the wet well and need to be pumped out.

  • What is the benefit of maintaining my lift station?

If you don't maintain your lift station you could find that both of your pumps have burned out.  You would then have to hire a pump out truck while costly repairs to your lift station are made.  During regular maintenance a failed pump will be found while the other pump is still running.  This gives the owner time to repair the pump which is not working while the lift station still operates normally.

  • Top 10 Lift Station Regular Maintenance Recommendations

The pumps, electronic controls and electrical works are under constant physical stress, and the corrosive environment requires constant maintenance repair. There is, however, a point where they need to be rebuilt with wholesale equipment replacement. On average that is about every 15 to 25 years. For larger capacity pumps it is recommended to rebuild at least one pump a minimum of every two years. Performance of routine and preventative maintenance can save station's owner from costly repair bills. The following are suggestions that may insure fewer breakdowns and problems:

1. Wet wells should be pumped out and cleaned at least twice a year, or more often if necessary, to prevent solids and grease build-up. Build-up of solids can create gases that can damage the pump, or sink and get caught in the impeller.
 
2. Inspection of submersible pumps should be performed quarterly. Inspection of the impeller should be performed quarterly or when motor hours are not within specifications. The inspections would assure that the impeller is free of debris or any other clogging material.
 
3. Inspection and greasing of the check valves should be performed at least twice a year to insure proper working order and to prevent back-flow from the force main to the wet well.
 
4. Cleaning and inspections of floats four times a year assure proper performance. The buildup of grease prevents floats from working properly.
 
5. Inspection of the light and alarm systems should be performed weekly. An alarm system in working order can alert you to problems immediately.
 
6. Installation of an hour meter on each motor will give one an accurate record of how often each motor is cycling; and hence, the amount of water being pumped through the system. A logbook of motor hours, dates and maintenance performed should be kept.
 
7. Amp readings should be taken at least once a month on each motor in the on-site lift station. If the amp readings do not meet the manufacturer's specifications, it is an indication that debris is lodged in the propeller within the motor, or that water has entered the motor housing or the wiring.
 
8. An inspection of all electrical motor control equipment to find poor connections and worn parts should be performed semi-annually.
 
9. Inspection and Cleaning of the basin, clean-outs, and covers should be performed to prevent build-up. In high corrosion prone environments all moving parts should operated and greased if necessary to ensure mechanical components are not at risk of failure.   
 
10. Good records can assist in every aspect of a lift station, if there is good record keeping you can instantly determine a problem with the system in some cases. For instance steadily increasing amp draw, or the hours of operation is steadily increasing on one pump and not the other. Records are needed to prove that system is operating properly, and can assist in determining if any future maintenance is required.