Basement bathroom plumbing options (pump up to septic line)

mrmichaeljmooreOctober 7, 2009

We are in the beginning stages of planning to install a full bathroom (stall shower, toilet, sink) in the basement of our ranch home.

We have a septic tank. The main waste line runs under the floor of the main floor (or ceiling of basement), then out to the septic tank. Therefore, we are gonna need some sort of system to pump up waste to the main waste line.

I have just begun to do some research on the options for pumping the sewage from the bathroom up to the waste line.

Preliminarily, it seems there are two options: break through the concrete to install a pump up system OR install a system that has the pump on the floor (such as the Liberty Pump system here:;c=21)

I am looking for opinions from the folks here on what are the best options....pros and cons.

Thanks for the help.

Here is a link that might be useful: L:iberty pump up system

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Either type of pump system will work equally well however before you begin ordering a sewage ejector pump and bathroom fixtures you need to determine if your house sewer line is large enough to handle the additional load.

By example, under the International Residential Code (IRC) all sewage ejector pumps MUST BE rated for a minimum discharge rate of 14.2GPM. To determine the load on the sewer line we are required to compute the load at 1.5 DFU's (Drainage Fixture Units for each gallon per minute from the pump, therefore the minimum load would be 14.2gpm x 1.5dfu = 21.3dfu's.

The gravity flow line receiving the discharge from the pump must be sized sufficiently to handle both the existing load on that line plus the additional 21.3dfu's from the pump.

Under no circumstances may the pump be discharged into a horizontal branch line because the code maximum for a 3" horizontal line is 20dfu.

The maximum allowable load for a 3" house main drain or house sewer line is 42dfu.

Before you begin you would need to make a list of all fixtures in the structure that are connected to the drainage system, then use the code tables to compute the existing DFU load.

Most residential structure today have a 3" main drain and house sewer which is generally more than adequate for a gravity flow DWV system, but when you add in the discharge load of a sewage ejection pump, in most instances it will require increasing the size of the house main drain from the point of tie in to 4" and the house sewer line from the structure to the septic tank will also need to be increased to 4".

    Bookmark   October 7, 2009 at 11:59AM
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Thanks for the info, lazypup.....

Since that is way beyond my plumbing knowledge, I hope my plumber takes that all into account. I will pass on this info to him for sure.

Is there anything else I need to be aware of when I have the plumber give me a quote?


    Bookmark   October 10, 2009 at 7:58PM
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Code requires that all sewage ejector pump assemblies must have a dedicated vent through the roof. It may not be connected to any other vents in the house. Sometimes it is very difficult to get a vent line from the basement through the roof.

    Bookmark   October 10, 2009 at 11:09PM
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My plumber and GC for my basement bathroom are coming tonight to look at the basement and go over the plans for the bathroom.

This will be the first time the plumber has seen the basement.

Basically, we are doing a full bath (toilet, stall shower, and sink) in our basement. Half of the basment is completely finished. We will be breaking through the wall of the finished side into the unfinished side for the bathroom.

House is on a septic system. We will need some sort of pump up system.
As suggested by the above thread, we will be breaking through the concrete and installing a sewage pump up system.

I just want to be prepared, so here are some questions I have:

Pump Up System --
1. What type of sewage ejector system is best? Grinder or Ejector?
2. What brands of pump up systems are best? Liberty? Zoeller? Little Giant?
3. Is there anything about installation of the pump up system that I should be aware of? Pipe size? Venting? Check valves? Plumbing codes? Etc? (Anything else in addition to what Lazypup has already said.......)

Septic system --
1. House is a 3 BR 1 Bath ranch. I beleive the septic tank is a 1000 gallon tank. Is there any problems in adding the additonal full bath?

Any bits of adivce/lessons learned/guidance you can give me to make sure my plumbing goes well for this project, it would be great.

Thank you.

    Bookmark   November 4, 2009 at 1:26PM
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