Before we begin I would like to clarify one point. The requirement to run a separate vent through the roof is not a manufacturers specification; it is a code requirement, which in this case is being emphasized by the manufacturer.

You may run the vent in the manner you describe subject to some rules.
1. The vent must rise vertical from the sewage ejector containment until it reaches a point that is at least 6" high than the flood level rim of the highest fixture served by the ejector. You stated that you are using the ejector for a bathroom group (tub/shower, lavatory & watercloset) therefore the highest flood level rim would be the lavatory countertop.
2. At the top of that vertical riser you must install a "Sanitary Tee" with the horizontal line connecting on the side inlet and you must install a thread adapter and cleanout plug on the top of the sani-tee.
3. The horizontal line from the vertical riser to the outside wall must be run with a " per foot pitch rising upwards from the vertical line to the outside wall. The horizontal line must be supported at not more than 48" increments.
4. To prevent frost closure the horizontal line must be increased to 3" at least one foot inside the structure. (Some jurisdictions require 4" to prevent frost closure, check your local AHJ).
5. If the line will be passing through a masonry wall the line must be sleeved. To make a sleeve you first install a short piece of line at least one nominal trade size larger than the desired pipe through the wall and extending out a minimum of 1" on either side. The sleeve may be sealed to the wall by any suitable means, I.E. cement, tar/pitch, expansion foam, etc.
6. Once the desired line is passed through the sleeve the space between the inner wall of the sleeve and the external wall of the desired pipe must be filled with expansion foam.
7. On the end of the horizontal line you must install a Wye & 1/8 bend or Combo with the side opening in the vertical position and a thread adapter and cleanout plug on the exterior end of the horizontal line. (Careful here, you must use a Wye & 1/8 bend or Combo. A sanitary tee would be prohibited here).
8. Some jurisdictions will permit running an exterior vent line however that is becoming more and more rare and in all cases it detracts from your overall property value, however if you enclose it in a race as you suggest it is then considered an integral part of the structure and you will be okay.
9. If the total developed length of the vent line exceeds 40Â you must increase all line sizes by one nominal trade size.
10. After the vent line passes through the roof it must continue upwards at least 6" above the roof or in region subject to snow, 6" higher than the listed average snowfall for your jurisdiction. (The measurement is to be taken on the vertical line from the high side of the roof slope to the top of the line.)
11. If your house is built close to the edge of your property be careful here, the vent opening must be a minimum of 10Â horizontal from the closest property line.
12. A vent must terminate a minimum of 7Â higher than the floor of any deck within 10Â horizontal.

Having said that, you should also be aware of the rules regarding where you can terminate the sewage ejection pump discharge line.

Sewage ejector pumps used in residential service usually have a 1-1/2 or 2" discharge line and many people assume that they may connect it to any 1-1/2" or 2" drain line in the structure but such is not the case. Keep in mind that the discharge from the sewage ejector is propelled by a pump therefore the gravity flow line receiving the discharge from the pump must be larger in order to handle the volume by means of gravity flow.

The code gives us some very strict requirements when sizing the discharge lines.

Under the IRC sewage ejector pumps must be rated at the actual gallon per minute of the pump or 14.2GPM, whichever is greater.

Once we know the Gal/min rate of the pump we must assign a value of 1.5DFUÂs (drainage fixture units) for each gallon per minute from the pump, therefore the minimum DFU load would be 14.2gpm x 1.5dfu = 21.3DFUÂs.

We must then compute the pre-existing load on the gravity flow line and add that value to the sewage ejection pump load value to determine the combined load.

Under the IRC a 3" horizontal branch line is rated for a maximum of 20DFUÂs therefore we cannot connect the sewage ejector to a branch line.

Under the IRC a 3" main drain or house sewer line is limited to a maximum of 42DFUÂs. This means that if your house has a 3" main drain and sewer line all existing fixtures in the house may not exceed 20.7DFUÂs.

Now let us consider the existing load:

Lavatory 1dfu
Tub 2dfu
Shower 2dfu
Tub/shower combo 3dfu
Watercloset (1.6gpf or less) 3dfu
Watercloset (greater than 1.6gpf) 4dfu
Bidet 1dfu
Kitchen sink 2dfu
Laundry standpipe 2dfu
Laundry sink 2dfu
Bar sink1dfu

From this table you will be able to compute the pre-existing load on your house main drain line. If the pre-existing load exceeds 20.7dfuÂs you cannot install a sewage ejector pump system unless your house main drain and house sewer lines are 4".

Note: The Uniform Plumbing Code uses different DFU values for fixtures and pipes but in the end it works out exactly the same.

Hi lazypup
Thank you for opening my eyes. I was about to run a 1-1/2" vent from the unit right out the wall and up through the eave of the roof. It never dawned on me that I had to go from 1-1/2" to 3". Makes perfect sense now that you've explained it ... I even understand why this is necessary.
I had already complied with you instructions #1 (6" above lavatory countertop), #2 (sanitary T with cleanout ) #3 (1/4" pitch).
I will now follow your instructions for #4 and transition to a 3" vent inside the house. As to #5, I will be exiting the house through the wooden header joist....do I still need a sleeve? #6 will be complied with whether sleeve is needed or not (foam). #8 is understood. #11 and #12 do not apply to my situation.

I do need clarification of the following: #7 - is this configuration correct?

I 3" vertical vent thru eave
/ 1/8 bend
3" vent inside then wall then Y w/plug outside: 3" inside____Y__/__ outside cleanout here
(assume part of Y can be inside as long as plug is outside)
NOTE: IN CASE THE ABOVE DOES NOT COME THRU THE WAY I TYPED IT, THIS IS THE SEQUENCE I AM TRYING TO COMMUNICATE: 3" INSIDE VENT TO OUTSIDE Y, CLEANOUT PLUG ON HORIZENTAL END, Y FACES UP AND CONNECTS TO 1/8 BEND WHICH CONNECTS TO 3" VENT THRU EAVE.

And finally #10: I assume you mean 6 inches above snow line and not 6 feet.

As to your comments re waste line, the unit I have requires only a 3/4" discharge pipe and won't work with anything larger. It pumps 23 gpm based on my configuration (it's rated up to 27 gpm with a different config).
Thus 23 gpm x 1.5 dfu's = 34.5 dfu's. BTW, you can view the unit at www.saniflo.com if your interested (model SaniBest).

I have a 3" main drain. Existing fixture = 1 Lavatory, 1 toilet (1.6 gpf), 1 tub/shower, 1 kitchen sink, 1 cloths washer for a total of 11 dfu's. The new bath will have 1 lavatory, 1 shower, 1 toilet (1.6 gpf) for a added 6 dfu's
Since I don't fully understand the application of the formula you provided, I'm asking you if this will work.

In closing, may I say how much I appreciate you advice. I have read probably a hundred+ of posts that you have responded to in the Home Site Plumbing Forum and am continually amazed and the depth of your knowledge and your willingness to help others.
Again, Thank you, Tom Cavacini (tradertom)

You have a slight error in your existing DFU load calculation. Your existing load is 1 lavatory (1DFU), 1 Toilet @1.6gpf (3DFU), 1 Tub/shower (2DFU), Kitchen sink (2DFU) and 1 Laundry Standpipe (2DFU) for a total load of 10DFUs.

A 3" main drain and House Sewer with a ¼"/ft pitch is rated for up to 42DFUs
If the House Sewer is laid with a 1/8" per foot pitch it is downgraded to 36DFUs
In either case with a total load of 10DFUs a 3" main drain and house sewer is more than adequate for the existing load on the house.

We do not add in the proposed fixtures that will discharge into the sewage ejector because they will be included in the sewage ejector computation.

Under the IRC to compute the DFU load of the sewage ejector we are required to begin with 14.2gpm or the actual GPM rating of the pump, whichever is greater, and allow 1.5DFUs for each GPM. You stated in your post that the pump you propose has a rating of 23GPM therefore the DFU load from the pump you propose would be 23gpm x 1.5dfu/gpm= 34.5DFU,s.

We would then add the pump discharge DFU load to the pre-existing DFU load to determine the combined DFU load on the main drain & sewer.

10DFU existing load + 34.5DFU pump load = 44.5DFU total load.

The combined DFU load is 44.5DFU but your 3" main drain and sewer is rated for a maximum of 42DFUs therefore to legally install the sewage ejector you would be required to increase the size of the house main drain downstream from the tie in point and the house sewer line to 4". You would also be required to change the house "Main Vent" from 3" to 4".

Sewage ejection pumps, as well as sump pumps, trash pumps, and marine bilge pumps are examples of Low Pressure-High volume pumps. The output volume of Low Pressure High Volume pumps drops off very quickly as the discharge vertical static head (vertical lift) is increased. With that in mind I went to the Sani-flow website and downloaded the operation and performance specifications for the Sani-Best pump hoping that the output might drop off enough with vertical rise to allow installing it however I discovered that the actual rating of this pump at the pump head is 30gpm and it drops off to 23gpm at an 8ft vertical rise so there is no help there.

The bottom line is that while installing an up flush system in the basement may initially seem like a simple solution, when all is said and done, in many cases it is far cheaper to build and addition on the house than to install a sewage ejection pump system.

Great explanation, can you just used a studor mini vent, ?

I nee this andwer also