The Saniflo unit is a sewage ejector pump and all sewage ejector pumps must be housed in a water tight vessel that has a separate dedicated vent through the roof. The sewage ejector pump vessel vent MAY NOT be attached to any other vents in the structure, and no other fixture vents may be attached to the sewage ejector vent.

An even greater problem is determining if your existing house "Main Drain" & "House Sewer" are large enough to handle the additional load of a sewage ejector pump system.

In order to answer your questions I would need additional information;

1. Which code are you under? If you don't know you could give us your city, county & state and I can find out what code applies to your area.

2. I would need a list of all fixtures in the house that are connected to the drain system in order to compute the existing load.

3. I would need to know the GPM output rating of the Saniflo unit you propose in order to compute the additional load.

4. Need to know the diameter of the existing "House Main Drain" & "House Sewer" lines.

5. Need to know the proposed fixture layout to determine if you will need additional fixture venting.

Thanks for your quick reply.

Since there is no way to vent through the roof (phyical structural constraints; I can vent through the side) I'd have to think of a different way to add this bathroom. Any ideas? The new bathroom would be about 8 feet below the main sewage pipe in the house, But since this bathroom would be in a new addition I can reach the main pipe going out to the septic tank.This is an almost horizontal pipe under the cement floor of the addition.

Here are answers to the questions you asked:

1. Southboro, MA 01772
2. Bathroom 1: sink, shower, toilet
Bathroom 2: Sink, Shower and toilet
Bathroom 3: Sink and Toilet
Kitchen: Sink
3. Here are the spec for the proposed Saniflo (again, if venting through the roof is a must, I'd need something else):
Motor RPM 3600
Horsepower 0.5
Electrical Supply 110-115V; 60Hz;
Flow rate at max head USG / MIN 15 ft:17 usg/min;3 ft:27usg
Amperage 4.5 AMP
Discharge Pipe Diameter 3/4" diameter
Vertical Discharge 15 ft
Horizontal Discharge 150 ft
Gravity fall on horizontal installations 1/4" per ft
Normal Running Time WC 10-15 seconds
Maximum Temperature 104°F

4. No idea. The house is about 50 years old, if this helps. It is a 4 bedroom colonial with 2 1/2 bathrooms

5. Shower and Toilet adjacent to each other. Sink at a 90 degrees wall from the shower and the sink

Thanks again for your advice.

Saniflo system is NOT a "sewage ejector pump".

It is a 'macerating toilet system' that does NOT REQUIRE a sewage ejector.

Also, it is not true that sewer ejectors "MAY NOT be attached to any other vents in the structure, and no other fixture vents may be attached to the sewage ejector vent". Whether they can or cannot depends entirely on your local plumbing code.

Both the IPC and IRC permit sewage ejectors (except pneumatic types) to be vented by tapping into existing vents without having to be on a dedicated vent of their own through the roof.

The IPC and IRC also permit air admittance valves to vent macerating toilet systems as well as sewage ejectors of the non-pneumatic variety.

Check with your local plumbing code officials before relying on internet plumbing advice which may not even apply to your jurisdiction.

Massachusetts Uniform State Plumbing Code 248 CMR 10.15(10)(d) and 10.16 absolutely permits sewage ejectors (except for pneumatic type) to also be vented in any manner approved by the code.

There is no requirement in Massachusetts for the vent from a Saniflo system to vent through the roof.

There is nothing in the Mass Code to prevent the Saniflo system to vent through the side wall.

It can vent by connecting into the existing venting system.

It can even vent (with permission) using an air-admittance valve.

Here is a link that might be useful: Massachusetts Uniform State Plumbing Code