Laundry Tub Pump

[mindless06795]

Hello,
I was wondering if anyone can recommend a good Waste Water Pump. Basically the pump that will sit under my laundry tub/sink to take the drain water from the sink / washer machines and pump it up to my City Drain.
Thank you

[LazyPup]

Before you begin selecting a pump the first step is to determine if it is even a viable option in your home.

The Plumbing Codes are very specific on the topic of pumping effluent waste. The only pumps that may be directly connected to the DWV (Drain, Waste & Vent) system are approved "Sewage Ejector Pumps".

In its simplest form a sewage ejection pump is a self contained submersible pump that is contained inside a watertight receiver vessel that must be fitted with a water tight removable cover. The vessel must then be fitted with a separate vent terminating through the roof of the structure. (The vent may not be connected to the normal DWV venting system.).

The discharge line from the sewage ejector pump must rise vertically to a point above the gravity flow line that it will discharge into. The connection to the gravity flow line must be made by means of a WYE with the side opening of the Wye on the top of the pipe.

The vertical riser from the sewage ejector must be fitted with a backflow preventer and a manual gate valve.

Under the International Residential Code(IRC) the minimum capacity of the pump must be 14.2gal/min. and the discharge load must be rated at 1.5 DFU's(drainage fixture units) for each gallon per minute. (Minimum 1.5DFU x 14.2gpm = 21.3DFU's.

Under the Uniform Plumbing Code the minimum capacity of the pump must be 20gal/min. and the discharge load must be computed at 2dfu for each gallon/minute. (minimum 2DFU x 20GPM = 40DFU's).

The pump must have a minimum 2" discharge line except, the IRC will permit an 1-1/2" if the pump is fitted with a macerator grinder but do not let this line size fool you. The point where you connect the discharge line to the house gravity flow line must large enough to handle the existing load on that line plus the rated DFU load of the pump.

Under the IRC a 3" branch line is only rated for a maximum of 20DFU and a 3" building main drain is only rated for a maximum of 36DFU. Understanding that a 3" main drain line is only rated for 36DFU and deducting the code minimum of 21.3DFU for the pump this means the existing load on the main drain cannot exceed 36 - 21.3 = 14.7DFU.

Now consider the existing load. A bathroom group is 6DFU and a kitchen sink is 2DFU. This means you can only have a maximum of two bathrooms and the kitchen plus the pump, otherwise you would need a 4" main drain and house sewer.

In the attached illustration you can see a sewage ejector that is set into a pit in the floor in the same manner as a sump pump. They also make self contained sewage ejector pumps that are contained in a plastic housing than can be set on the floor but they must also meet all the code restrictions outlined above.