Grinder pump

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A grinder pump is a waste management device. Waste from water-using household appliances (toilets, bathtubs, washing machines, etc.) flows through the home’s pipes into the grinder pump’s holding tank. Once the waste inside the tank reaches a certain level, the pump will turn on, grind the waste into a fine slurry, and pump it to the central sewer system.

Grinder pumps can be installed in the basement or in the yard. If installed in the yard, the holding tank must be buried deep enough that the pump and sewage pipes are below the frost line.

There are two types of grinder pumps, semi-positive displacement (SPD) and centrifugal.

[edit] Components

The grinder pump “station” consists of the pump, a tank, and an alarm panel. A pump for household use is usually 1 hp, 1.5 hp or 2 hp. A cutting mechanism macerates waste and grinds items that are not normally found in sewage, but may get flushed down the toilet. The pump has a level sensor either built into the pump, called “sensing bells,” or attached externally to the pump, called “floats.” (The level sensing devices vary among grinder pump manufacturers.)

If the pump malfunctions and the waste level in the holding tank rises above a certain level, the alarm panel should alert the homeowner that the pump is experiencing problems. The alarm panel should have both a buzzer and an indicator light.

The holding tank, likely constructed of fiberglass, HDPE or FRP, has an inlet opening and a discharge opening. The pipes from the home are connected to the inlet; the pipe that leads to the sewer main is connected to the discharge. The tank has a lid made from heavy-duty plastic or metal that is bolted and/or padlocked shut to prevent entry by unauthorized persons.

[edit] Maintenance

Grinder pumps should not require preventive maintenance. However, grinder pumps that use floats to sense the level in the holding tank are prone to grease buildup that may turn the pump on unnecessarily, or not turn on the pump at all, causing the tank to fill up and sewage to possibly back up into the home.

Homeowners are not usually limited by what they can or can not pour down their drains because their home has a grinder pump. Sanitary napkins, diapers, kitty litter, paint, oil, etc. should not be flushed or poured down any drain, whether the home is connected to a gravity sewer system, septic tank, grinder pump or cesspool.

Self-repair is not recommended. Contact the sewer district or the grinder pump manufacturer, who should refer you to an authorized service dealer, for repair.